Always use _typeshed.Self, where applicable (#6880)

* Always use `_typeshed.Self`, where applicable

* Revert changes to `google-cloud-ndb` (ambiguous)

* Remove empty line added by script

* Revert changes to `stubs/python-dateutil/dateutil/relativedelta.pyi`

* Manually add a few more that the script missed

* Improve `filelock` annotation

Source code here: https://github.com/tox-dev/py-filelock/blob/79ec7b2826e33b982fe83b057f359448b9d966ba/src/filelock/_api.py#L207

* Improve `opentracing/scope` annotation

Source code here: https://github.com/opentracing/opentracing-python/blob/3e1d357a348269ef54d67f761302fab93dbfc0f7/opentracing/scope.py#L71

* Improve `redis/client` stub

Source code here: https://github.com/redis/redis-py/blob/15f315a496c3267c8cbcc6d6d9c6005ea4d4a4d5/redis/client.py#L1217

* Improve `redis/lock` annotation

Source code here: https://github.com/redis/redis-py/blob/15f315a496c3267c8cbcc6d6d9c6005ea4d4a4d5/redis/lock.py#L155

* Improve `requests/models` annotation

Source code here: https://github.com/psf/requests/blob/d718e753834b84018014a23d663369ac27d1ab9c/requests/models.py#L653

stdlib/functools.pyi

@@ -1,6 +1,6 @@
 import sys
 import types
-from _typeshed import SupportsAllComparisons, SupportsItems
+from _typeshed import Self, SupportsAllComparisons, SupportsItems
 from typing import Any, Callable, Generic, Hashable, Iterable, NamedTuple, Sequence, Sized, TypeVar, overload
 from typing_extensions import final
 
@@ -51,7 +51,7 @@ class partial(Generic[_T]):
     func: Callable[..., _T]
     args: tuple[Any, ...]
     keywords: dict[str, Any]
-    def __new__(cls: type[_S], __func: Callable[..., _T], *args: Any, **kwargs: Any) -> _S: ...
+    def __new__(cls: type[Self], __func: Callable[..., _T], *args: Any, **kwargs: Any) -> Self: ...
     def __call__(__self, *args: Any, **kwargs: Any) -> _T: ...
     if sys.version_info >= (3, 9):
         def __class_getitem__(cls, item: Any) -> GenericAlias: ...