docs: add minimum versions to the command pages

cmd/cleanup/cleanup.go

@@ -20,6 +20,9 @@ var commandDefinition = &cobra.Command{
 Clean up the remote if possible.  Empty the trash or delete old file
 versions. Not supported by all remotes.
 `,
+	Annotations: map[string]string{
+		"versionIntroduced": "v1.31",
+	},
 	Run: func(command *cobra.Command, args []string) {
 		cmd.CheckArgs(1, 1, command, args)
 		fsrc := cmd.NewFsSrc(args)