docs: update markdown format (#3260)

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

README.md

@@ -14,7 +14,6 @@
 
 Gin is a web framework written in Go (Golang). It features a martini-like API with performance that is up to 40 times faster thanks to [httprouter](https://github.com/julienschmidt/httprouter). If you need performance and good productivity, you will love Gin.
 
-
 ## Contents
 
 - [Gin Web Framework](#gin-web-framework)
@@ -23,7 +22,7 @@ Gin is a web framework written in Go (Golang). It features a martini-like API wi
   - [Quick start](#quick-start)
   - [Benchmarks](#benchmarks)
   - [Gin v1. stable](#gin-v1-stable)
-  - [Build with jsoniter/go-json](#build-with-json-replacement)
+  - [Build with json replacement](#build-with-json-replacement)
   - [Build without `MsgPack` rendering feature](#build-without-msgpack-rendering-feature)
   - [API Examples](#api-examples)
     - [Using GET, POST, PUT, PATCH, DELETE and OPTIONS](#using-get-post-put-patch-delete-and-options)
@@ -38,6 +37,7 @@ Gin is a web framework written in Go (Golang). It features a martini-like API wi
     - [Grouping routes](#grouping-routes)
     - [Blank Gin without middleware by default](#blank-gin-without-middleware-by-default)
     - [Using middleware](#using-middleware)
+    - [Custom Recovery behavior](#custom-recovery-behavior)
     - [How to write log file](#how-to-write-log-file)
     - [Custom Log Format](#custom-log-format)
     - [Controlling Log output coloring](#controlling-log-output-coloring)
@@ -75,6 +75,7 @@ Gin is a web framework written in Go (Golang). It features a martini-like API wi
     - [Build a single binary with templates](#build-a-single-binary-with-templates)
     - [Bind form-data request with custom struct](#bind-form-data-request-with-custom-struct)
     - [Try to bind body into different structs](#try-to-bind-body-into-different-structs)
+    - [Bind form-data request with custom struct and custom tag](#bind-form-data-request-with-custom-struct-and-custom-tag)
     - [http2 server push](#http2-server-push)
     - [Define format for the log of routes](#define-format-for-the-log-of-routes)
     - [Set and get a cookie](#set-and-get-a-cookie)
@@ -89,7 +90,7 @@ To install Gin package, you need to install Go and set your Go workspace first.
 1. You first need [Go](https://golang.org/) installed (**version 1.15+ is required**), then you can use the below Go command to install Gin.
 
 ```sh
-$ go get -u github.com/gin-gonic/gin
+go get -u github.com/gin-gonic/gin
 ```
 
 2. Import it in your code:
@@ -193,12 +194,15 @@ Gin uses a custom version of [HttpRouter](https://github.com/julienschmidt/httpr
 Gin uses `encoding/json` as default json package but you can change it by build from other tags.
 
 [jsoniter](https://github.com/json-iterator/go)
+
 ```sh
-$ go build -tags=jsoniter .
+go build -tags=jsoniter .
 ```
+
 [go-json](https://github.com/goccy/go-json)
+
 ```sh
-$ go build -tags=go_json .
+go build -tags=go_json .
 ```
 
 ## Build without `MsgPack` rendering feature
@@ -206,7 +210,7 @@ $ go build -tags=go_json .
 Gin enables `MsgPack` rendering feature by default. But you can disable this feature by specifying `nomsgpack` build tag.
 
 ```sh
-$ go build -tags=nomsgpack .
+go build -tags=nomsgpack .
 ```
 
 This is useful to reduce the binary size of executable files. See the [detail information](https://github.com/gin-gonic/gin/pull/1852).
@@ -316,7 +320,7 @@ func main() {
 
 ### Another example: query + post form
 
-```
+```sh
 POST /post?id=1234&page=1 HTTP/1.1
 Content-Type: application/x-www-form-urlencoded
 
@@ -340,13 +344,13 @@ func main() {
 }
 ```
 
-```
+```sh
 id: 1234; page: 1; name: manu; message: this_is_great
 ```
 
 ### Map as querystring or postform parameters
 
-```
+```sh
 POST /post?ids[a]=1234&ids[b]=hello HTTP/1.1
 Content-Type: application/x-www-form-urlencoded
 
@@ -368,7 +372,7 @@ func main() {
 }
 ```
 
-```
+```sh
 ids: map[b:hello a:1234]; names: map[second:tianou first:thinkerou]
 ```
 
@@ -485,8 +489,8 @@ instead of
 r := gin.Default()
 ```
 
-
 ### Using middleware
+
 ```go
 func main() {
   // Creates a router without any middleware by default
@@ -527,6 +531,7 @@ func main() {
 ```
 
 ### Custom Recovery behavior
+
 ```go
 func main() {
   // Creates a router without any middleware by default
@@ -560,6 +565,7 @@ func main() {
 ```
 
 ### How to write log file
+
 ```go
 func main() {
     // Disable Console Color, you don't need console color when writing the logs to file.
@@ -582,6 +588,7 @@ func main() {
 ```
 
 ### Custom Log Format
+
 ```go
 func main() {
   router := gin.New()
@@ -613,8 +620,9 @@ func main() {
 }
 ```
 
-**Sample Output**
+Sample Output
-```
+
+```sh
 ::1 - [Fri, 07 Dec 2018 17:04:38 JST] "GET /ping HTTP/1.1 200 122.767µs "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.80 Safari/537.36" "
 ```
 
@@ -669,6 +677,7 @@ Gin uses [**go-playground/validator/v10**](https://github.com/go-playground/vali
 Note that you need to set the corresponding binding tag on all fields you want to bind. For example, when binding from JSON, set `json:"fieldname"`.
 
 Also, Gin provides two sets of methods for binding:
+
 - **Type** - Must bind
   - **Methods** - `Bind`, `BindJSON`, `BindXML`, `BindQuery`, `BindYAML`, `BindHeader`, `BindTOML`
   - **Behavior** - These methods use `MustBindWith` under the hood. If there is a binding error, the request is aborted with `c.AbortWithError(400, err).SetType(ErrorTypeBind)`. This sets the response status code to 400 and the `Content-Type` header is set to `text/plain; charset=utf-8`. Note that if you try to set the response code after this, it will result in a warning `[GIN-debug] [WARNING] Headers were already written. Wanted to override status code 400 with 422`. If you wish to have greater control over the behavior, consider using the `ShouldBind` equivalent method.
@@ -749,8 +758,9 @@ func main() {
 }
 ```
 
-**Sample request**
+Sample request
-```shell
+
+```sh
 $ curl -v -X POST \
   http://localhost:8080/loginJSON \
   -H 'content-type: application/json' \
@@ -771,9 +781,7 @@ $ curl -v -X POST \
 {"error":"Key: 'Login.Password' Error:Field validation for 'Password' failed on the 'required' tag"}
 ```
 
-**Skip validate**
+Skip validate: when running the above example using the above the `curl` command, it returns error. Because the example use `binding:"required"` for `Password`. If use `binding:"-"` for `Password`, then it will not return error when running the above example again.
-
-When running the above example using the above the `curl` command, it returns error. Because the example use `binding:"required"` for `Password`. If use `binding:"-"` for `Password`, then it will not return error when running the above example again.
 
 ### Custom Validators
 
@@ -927,8 +935,9 @@ func startPage(c *gin.Context) {
 ```
 
 Test it with:
+
 ```sh
-$ curl -X GET "localhost:8085/testing?name=appleboy&address=xyz&birthday=1992-03-15&createTime=1562400033000000123&unixTime=1562400033"
+curl -X GET "localhost:8085/testing?name=appleboy&address=xyz&birthday=1992-03-15&createTime=1562400033000000123&unixTime=1562400033"
 ```
 
 ### Bind Uri
@@ -964,9 +973,10 @@ func main() {
 ```
 
 Test it with:
+
 ```sh
-$ curl -v localhost:8088/thinkerou/987fbc97-4bed-5078-9f07-9141ba07c9f3
+curl -v localhost:8088/thinkerou/987fbc97-4bed-5078-9f07-9141ba07c9f3
-$ curl -v localhost:8088/thinkerou/not-uuid
+curl -v localhost:8088/thinkerou/not-uuid
 ```
 
 ### Bind Header
@@ -1050,7 +1060,7 @@ form.html
 
 result:
 
-```
+```json
 {"color":["red","green","blue"]}
 ```
 
@@ -1093,8 +1103,9 @@ func main() {
 ```
 
 Test it with:
+
 ```sh
-$ curl -X POST -v --form name=user --form "avatar=@./avatar.png" http://localhost:8080/profile
+curl -X POST -v --form name=user --form "avatar=@./avatar.png" http://localhost:8080/profile
 ```
 
 ### XML, JSON, YAML and ProtoBuf rendering
@@ -1171,6 +1182,7 @@ func main() {
   r.Run(":8080")
 }
 ```
+
 #### JSONP
 
 Using JSONP to request data from a server  in a different domain. Add callback to response body if the query parameter callback exists.
@@ -1452,7 +1464,8 @@ Date: {[{.now | formatAsDate}]}
 ```
 
 Result:
-```
+
+```sh
 Date: 2017/07/01
 ```
 
@@ -1471,6 +1484,7 @@ r.GET("/test", func(c *gin.Context) {
 ```
 
 Issuing a HTTP redirect from POST. Refer to issue: [#444](https://github.com/gin-gonic/gin/issues/444)
+
 ```go
 r.POST("/test", func(c *gin.Context) {
   c.Redirect(http.StatusFound, "/foo")
@@ -1489,7 +1503,6 @@ r.GET("/test2", func(c *gin.Context) {
 })
 ```
 
-
 ### Custom Middleware
 
 ```go
@@ -1612,6 +1625,7 @@ func main() {
   http.ListenAndServe(":8080", router)
 }
 ```
+
 or
 
 ```go
@@ -1794,9 +1808,9 @@ endless.ListenAndServe(":4242", router)
 
 Alternatives:
 
-* [manners](https://github.com/braintree/manners): A polite Go HTTP server that shuts down gracefully.
-* [graceful](https://github.com/tylerb/graceful): Graceful is a Go package enabling graceful shutdown of an http.Handler server.
 * [grace](https://github.com/facebookgo/grace): Graceful restart & zero downtime deploy for Go servers.
+* [graceful](https://github.com/tylerb/graceful): Graceful is a Go package enabling graceful shutdown of an http.Handler server.
+* [manners](https://github.com/braintree/manners): A polite Go HTTP server that shuts down gracefully.
 
 #### Manually
 
@@ -1972,7 +1986,7 @@ func main() {
 
 Using the command `curl` command result:
 
-```
+```sh
 $ curl "http://localhost:8080/getb?field_a=hello&field_b=world"
 {"a":{"FieldA":"hello"},"b":"world"}
 $ curl "http://localhost:8080/getc?field_a=hello&field_c=world"
@@ -2031,10 +2045,10 @@ func SomeHandler(c *gin.Context) {
 }
 ```
 
-* `c.ShouldBindBodyWith` stores body into the context before binding. This has
+1. `c.ShouldBindBodyWith` stores body into the context before binding. This has
 a slight impact to performance, so you should not use this method if you are
 enough to call binding at once.
-* This feature is only needed for some formats -- `JSON`, `XML`, `MsgPack`,
+2. This feature is only needed for some formats -- `JSON`, `XML`, `MsgPack`,
 `ProtoBuf`. For other formats, `Query`, `Form`, `FormPost`, `FormMultipart`,
 can be called by `c.ShouldBind()` multiple times without any damage to
 performance (See [#1341](https://github.com/gin-gonic/gin/pull/1341)).
@@ -2146,7 +2160,8 @@ func main() {
 ### Define format for the log of routes
 
 The default log of routes is:
-```
+
+```sh
 [GIN-debug] POST   /foo                      --> main.main.func1 (3 handlers)
 [GIN-debug] GET    /bar                      --> main.main.func2 (3 handlers)
 [GIN-debug] GET    /status                   --> main.main.func3 (3 handlers)
@@ -2154,6 +2169,7 @@ The default log of routes is:
 
 If you want to log this information in given format (e.g. JSON, key values or something else), then you can define this format with `gin.DebugPrintRouteFunc`.
 In the example below, we log all routes with standard log package but you can use another log tools that suits of your needs.
+
 ```go
 import (
   "log"
@@ -2257,6 +2273,7 @@ func main() {
 **Notice:** If you are using a CDN service, you can set the `Engine.TrustedPlatform`
 to skip TrustedProxies check, it has a higher priority than TrustedProxies. 
 Look at the example below:
+
 ```go
 import (
   "fmt"
@@ -2345,4 +2362,3 @@ Awesome project lists using [Gin](https://github.com/gin-gonic/gin) web framewor
 * [picfit](https://github.com/thoas/picfit): An image resizing server written in Go.
 * [brigade](https://github.com/brigadecore/brigade): Event-based Scripting for Kubernetes.
 * [dkron](https://github.com/distribworks/dkron): Distributed, fault tolerant job scheduling system.
-