only rewrite utility files if contents changed

scripts/completion_bash.py

@@ -48,7 +48,7 @@ for action in option.build_parser()._actions:
             opts.append(opt)
 
 PATH = util.path("data/completion/gallery-dl")
-with open(PATH, "w", encoding="utf-8") as file:
+with util.lazy(PATH) as file:
     file.write(TEMPLATE % {
         "opts"    : " ".join(opts),
         "diropts" : "|".join(diropts),