[3.13] remove type annotations from multiprocessing. (GH-129381) (#129470)

remove type annotations from multiprocessing. (GH-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



---------
(cherry picked from commit 71aecc284e)

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

Lib/multiprocessing/synchronize.py

@@ -360,7 +360,7 @@ 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}>"
 #