[3.15] gh-150285: Suppress showing the __getstate__() comment in the help for dataclasses (GH-151328) (GH-151331)

(cherry picked from commit 0066fd7)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Author: miss-islington

Lib/dataclasses.py

@@ -1250,6 +1250,7 @@ def _process_class(cls, init, repr, eq, order, unsafe_hash, frozen,
 # classes with slots.  These could be slightly more performant if we generated
 # the code instead of iterating over fields.  But that can be a project for
 # another day, if performance becomes an issue.
+
 def _dataclass_getstate(self):
     return [getattr(self, f.name) for f in fields(self)]