Merge branch 'sg/worktree-remove-errormsg'

Error message update/clarification.

* sg/worktree-remove-errormsg:
  worktree remove: clarify error message on dirty worktree

Author: gitster

builtin/worktree.c

@@ -880,7 +880,7 @@ static void check_clean_worktree(struct worktree *wt,
 			  original_path);
 	ret = xread(cp.out, buf, sizeof(buf));
 	if (ret)
-		die(_("'%s' is dirty, use --force to delete it"),
+		die(_("'%s' contains modified or untracked files, use --force to delete it"),
 		    original_path);
 	close(cp.out);
 	ret = finish_command(&cp);