stdlib: add many missing __del__ methods (#11042)

stdlib/sunau.pyi

@@ -34,6 +34,7 @@ class Au_read:
     def __init__(self, f: _File) -> None: ...
     def __enter__(self) -> Self: ...
     def __exit__(self, *args: Unused) -> None: ...
+    def __del__(self) -> None: ...
     def getfp(self) -> IO[bytes] | None: ...
     def rewind(self) -> None: ...
     def close(self) -> None: ...
@@ -54,6 +55,7 @@ class Au_write:
     def __init__(self, f: _File) -> None: ...
     def __enter__(self) -> Self: ...
     def __exit__(self, *args: Unused) -> None: ...
+    def __del__(self) -> None: ...
     def setnchannels(self, nchannels: int) -> None: ...
     def getnchannels(self) -> int: ...
     def setsampwidth(self, sampwidth: int) -> None: ...