remove type annotations from multiprocessing. (#129381)

* remove type annotations from multiprocessing.

One of them was technically invalid per typing specs... but since we're not
checking these in the stdlib today lets elide them.

https://discuss.python.org/t/static-type-annotations-in-cpython/65068/13

* use the actual comment style annotation format

Co-authored-by: 🇺🇦 Sviatoslav Sydorenko (Святослав Сидоренко) <wk.cvs.github@sydorenko.org.ua>

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Co-authored-by: 🇺🇦 Sviatoslav Sydorenko (Святослав Сидоренко) <wk.cvs.github@sydorenko.org.ua>

Lib/multiprocessing/connection.py

@@ -853,7 +853,7 @@ _MD5_DIGEST_LEN = 16
 _LEGACY_LENGTHS = (_MD5ONLY_MESSAGE_LENGTH, _MD5_DIGEST_LEN)
 
 
-def _get_digest_name_and_payload(message: bytes) -> (str, bytes):
+def _get_digest_name_and_payload(message):  # type: (bytes) -> tuple[str, bytes]
     """Returns a digest name and the payload for a response hash.
 
     If a legacy protocol is detected based on the message length

Lib/multiprocessing/synchronize.py

@@ -359,7 +359,7 @@ class Event(object):
                 return True
             return False
 
-    def __repr__(self) -> str:
+    def __repr__(self):
         set_status = 'set' if self.is_set() else 'unset'
         return f"<{type(self).__qualname__} at {id(self):#x} {set_status}>"
 #