Switch cmd/ to use constructor functions. (#36962)

This is a step towards potentially splitting command groups into their
own folders to clean up `cmd/` as one folder for all cli commands.
Returning fresh command instances will also aid in adding tests as you
don't need to concern yourself with the whole command tree being one
mutable variable.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

cmd/docs.go

@@ -13,23 +13,24 @@ import (
 	"github.com/urfave/cli/v3"
 )
 
-// CmdDocs represents the available docs sub-command.
-var CmdDocs = &cli.Command{
-	Name:        "docs",
-	Usage:       "Output CLI documentation",
-	Description: "A command to output Gitea's CLI documentation, optionally to a file.",
-	Action:      runDocs,
-	Flags: []cli.Flag{
-		&cli.BoolFlag{
-			Name:  "man",
-			Usage: "Output man pages instead",
+func newDocsCommand() *cli.Command {
+	return &cli.Command{
+		Name:        "docs",
+		Usage:       "Output CLI documentation",
+		Description: "A command to output Gitea's CLI documentation, optionally to a file.",
+		Action:      runDocs,
+		Flags: []cli.Flag{
+			&cli.BoolFlag{
+				Name:  "man",
+				Usage: "Output man pages instead",
+			},
+			&cli.StringFlag{
+				Name:    "output",
+				Aliases: []string{"o"},
+				Usage:   "Path to output to instead of stdout (will overwrite if exists)",
+			},
 		},
-		&cli.StringFlag{
-			Name:    "output",
-			Aliases: []string{"o"},
-			Usage:   "Path to output to instead of stdout (will overwrite if exists)",
-		},
-	},
+	}
 }
 
 func runDocs(_ context.Context, cmd *cli.Command) error {