chore: add some annotations (#1544)

ref: #1075 
because I am not a native English, maybe have a bit problem.

utils.go

@@ -14,8 +14,10 @@ import (
 	"strings"
 )
 
+// BindKey indicates a default bind key.
 const BindKey = "_gin-gonic/gin/bindkey"
 
+// Bind is a helper function for given interface object and returns a Gin middleware.
 func Bind(val interface{}) HandlerFunc {
 	value := reflect.ValueOf(val)
 	if value.Kind() == reflect.Ptr {
@@ -33,16 +35,14 @@ func Bind(val interface{}) HandlerFunc {
 	}
 }
 
-// WrapF is a helper function for wrapping http.HandlerFunc
-// Returns a Gin middleware
+// WrapF is a helper function for wrapping http.HandlerFunc and returns a Gin middleware.
 func WrapF(f http.HandlerFunc) HandlerFunc {
 	return func(c *Context) {
 		f(c.Writer, c.Request)
 	}
 }
 
-// WrapH is a helper function for wrapping http.Handler
-// Returns a Gin middleware
+// WrapH is a helper function for wrapping http.Handler and returns a Gin middleware.
 func WrapH(h http.Handler) HandlerFunc {
 	return func(c *Context) {
 		h.ServeHTTP(c.Writer, c.Request)