use custom warning format

autopep8.py

@@ -159,6 +159,10 @@ class documentation for more information.
     IS_SUPPORT_TOKEN_FSTRING = True
 
 
+def _custom_formatwarning(message, category, _, __, line=None):
+    return f"{category.__name__}: {message}\n"
+
+
 def open_with_encoding(filename, mode='r', encoding=None, limit_byte_check=-1):
     """Return opened file with a specific encoding."""
     if not encoding:
@@ -3965,8 +3969,11 @@ def parse_args(arguments, apply_config=False):
                 'to the second',
             )
 
+    original_formatwarning = warnings.formatwarning
+    warnings.formatwarning = _custom_formatwarning
     if args.experimental:
         warnings.warn("`experimental` option is deprecated and will be removed in a future version.", DeprecationWarning)
+    warnings.formatwarning = original_formatwarning
 
     return args