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/zoneinfo/__init__.pyi

@@ -1,5 +1,5 @@
 import typing
-from _typeshed import StrPath
+from _typeshed import Self, StrPath
 from datetime import tzinfo
 from typing import Any, Iterable, Protocol, Sequence
 
@@ -14,9 +14,9 @@ class ZoneInfo(tzinfo):
     def key(self) -> str: ...
     def __init__(self, key: str) -> None: ...
     @classmethod
-    def no_cache(cls: type[_T], key: str) -> _T: ...
+    def no_cache(cls: type[Self], key: str) -> Self: ...
     @classmethod
-    def from_file(cls: type[_T], __fobj: _IOBytes, key: str | None = ...) -> _T: ...
+    def from_file(cls: type[Self], __fobj: _IOBytes, key: str | None = ...) -> Self: ...
     @classmethod
     def clear_cache(cls, *, only_keys: Iterable[str] = ...) -> None: ...