Add filters to stdlib/warnings.pyi (#5889)

stdlib/warnings.pyi

@@ -1,9 +1,11 @@
 from types import ModuleType, TracebackType
-from typing import Any, TextIO, Type, overload
+from typing import Any, Sequence, TextIO, Type, overload
 from typing_extensions import Literal
 
 from _warnings import warn as warn, warn_explicit as warn_explicit
 
+filters: Sequence[tuple[str, str | None, Type[Warning], str | None, int]]  # undocumented, do not mutate
+
 def showwarning(
     message: Warning | str, category: Type[Warning], filename: str, lineno: int, file: TextIO | None = ..., line: str | None = ...
 ) -> None: ...