docs: typing.Self, fix typo (GH-94771)

* fix typo - double spelled word 'use'

* change methods names to the infinitive form
(cherry picked from commit 90a6e56e56)

Co-authored-by: Max Zhenzhera <59729293+maxzhenzhera@users.noreply.github.com>

Lib/typing.py

@@ -569,7 +569,7 @@ def Self(self, parameters):
       from typing import Self
 
       class Foo:
-          def returns_self(self) -> Self:
+          def return_self(self) -> Self:
               ...
               return self