group commands and make features/options visible

cmd/restic/cmd_diff.go

@@ -45,6 +45,7 @@ Exit status is 10 if the repository does not exist.
 Exit status is 11 if the repository is already locked.
 Exit status is 12 if the password is incorrect.
 `,
+	GroupID:           cmdGroupDefault,
 	DisableAutoGenTag: true,
 	RunE: func(cmd *cobra.Command, args []string) error {
 		return runDiff(cmd.Context(), diffOptions, globalOptions, args)