Revert changes to wrting_stubs that should be made separately.

Author: rchen152

docs/guides/writing_stubs.rst

@@ -337,46 +337,6 @@ No::
     DAY_FLAG: int
     NIGHT_FLAG: int
 
-Overloads
----------
-
-All variants of overloaded functions and methods must have an ``@overload``
-decorator. Do not include the implementation's final non-`@overload`-decorated
-definition.
-
-Yes::
-
-  @overload
-  def foo(x: str) -> str: ...
-  @overload
-  def foo(x: float) -> int: ...
-
-No::
-
-  @overload
-  def foo(x: str) -> str: ...
-  @overload
-  def foo(x: float) -> int: ...
-  def foo(x: str | float) -> Any: ...
-
-Decorators
-----------
-
-Include only the decorators listed :ref:`here <stub-decorators>`, whose effects
-are understood by all of the major type checkers. The behavior of other
-decorators should instead be incorporated into the types. For example, for the
-following function::
-
-  import contextlib
-  @contextlib.contextmanager
-  def f():
-      yield 42
-
-the stub definition should be::
-
-  from contextlib import AbstractContextManager
-  def f() -> AbstractContextManager[int]: ...
-
 Documentation or Implementation
 -------------------------------
 
@@ -621,30 +581,3 @@ No::
     from typing import NamedTuple, TypedDict
     Point = NamedTuple("Point", [('x', float), ('y', float)])
     Thing = TypedDict("Thing", {'stuff': str, 'index': int})
-
-Built-in Generics
------------------
-
-:pep:`585` built-in generics are supported and should be used instead
-of the corresponding types from ``typing``::
-
-    from collections import defaultdict
-
-    def foo(t: type[MyClass]) -> list[int]: ...
-    x: defaultdict[int]
-
-Using imports from ``collections.abc`` instead of ``typing`` is
-generally possible and recommended::
-
-    from collections.abc import Iterable
-
-    def foo(iter: Iterable[int]) -> None: ...
-
-Unions
-------
-
-Declaring unions with the shorthand `|` syntax is recommended and supported by
-all type checkers::
-
-  def foo(x: int | str) -> int | None: ...  # recommended
-  def foo(x: Union[int, str]) -> Optional[int]: ...  # ok