Fix pywin32's PyCBitmap.GetBitmapBits method (#11108)

Author: Avasam

stubs/pywin32/_win32typing.pyi

@@ -4801,7 +4801,12 @@ class PyCBitmap:
         arg1: tuple[Incomplete, Incomplete, Incomplete, Incomplete],
     ) -> None: ...
     def GetInfo(self): ...
-    def GetBitmapBits(self, asString: int = ...) -> str: ...
+    @overload
+    def GetBitmapBits(self, __asString: Literal[False] = False) -> tuple[int, ...]: ...
+    @overload
+    def GetBitmapBits(self, __asString: Literal[True]) -> bytes: ...
+    @overload
+    def GetBitmapBits(self, __asString: bool) -> tuple[int, ...] | bytes: ...
     def SaveBitmapFile(self, dcObject: PyCDC, Filename: str): ...
 
 class PyCBrush: