Add keeporder to shell completion (#1903)

This allows programs to request the shell to maintain the order of completions that was returned by the program

zsh_completions.go

@@ -108,8 +108,9 @@ _%[1]s()
     local shellCompDirectiveNoFileComp=%[5]d
     local shellCompDirectiveFilterFileExt=%[6]d
     local shellCompDirectiveFilterDirs=%[7]d
+    local shellCompDirectiveKeepOrder=%[8]d
 
-    local lastParam lastChar flagPrefix requestComp out directive comp lastComp noSpace
+    local lastParam lastChar flagPrefix requestComp out directive comp lastComp noSpace keepOrder
     local -a completions
 
     __%[1]s_debug "\n========= starting completion logic =========="
@@ -177,7 +178,7 @@ _%[1]s()
         return
     fi
 
-    local activeHelpMarker="%[8]s"
+    local activeHelpMarker="%[9]s"
     local endIndex=${#activeHelpMarker}
     local startIndex=$((${#activeHelpMarker}+1))
     local hasActiveHelp=0
@@ -227,6 +228,11 @@ _%[1]s()
         noSpace="-S ''"
     fi
 
+    if [ $((directive & shellCompDirectiveKeepOrder)) -ne 0 ]; then
+        __%[1]s_debug "Activating keep order."
+        keepOrder="-V"
+    fi
+
     if [ $((directive & shellCompDirectiveFilterFileExt)) -ne 0 ]; then
         # File extension filtering
         local filteringCmd
@@ -262,7 +268,7 @@ _%[1]s()
         return $result
     else
         __%[1]s_debug "Calling _describe"
-        if eval _describe "completions" completions $flagPrefix $noSpace; then
+        if eval _describe $keepOrder "completions" completions $flagPrefix $noSpace; then
             __%[1]s_debug "_describe found some completions"
 
             # Return the success of having called _describe
@@ -296,6 +302,6 @@ if [ "$funcstack[1]" = "_%[1]s" ]; then
 fi
 `, name, compCmd,
 		ShellCompDirectiveError, ShellCompDirectiveNoSpace, ShellCompDirectiveNoFileComp,
-		ShellCompDirectiveFilterFileExt, ShellCompDirectiveFilterDirs,
+		ShellCompDirectiveFilterFileExt, ShellCompDirectiveFilterDirs, ShellCompDirectiveKeepOrder,
 		activeHelpMarker))
 }