Fix loop.remove_reader() and loop.remove_writer() return types (#7042)

Author: asvetlov

stdlib/asyncio/base_events.pyi

@@ -353,9 +353,9 @@ class BaseEventLoop(AbstractEventLoop, metaclass=ABCMeta):
         **kwargs: Any,
     ) -> tuple[SubprocessTransport, _ProtocolT]: ...
     def add_reader(self, fd: FileDescriptorLike, callback: Callable[..., Any], *args: Any) -> None: ...
-    def remove_reader(self, fd: FileDescriptorLike) -> None: ...
+    def remove_reader(self, fd: FileDescriptorLike) -> bool: ...
     def add_writer(self, fd: FileDescriptorLike, callback: Callable[..., Any], *args: Any) -> None: ...
-    def remove_writer(self, fd: FileDescriptorLike) -> None: ...
+    def remove_writer(self, fd: FileDescriptorLike) -> bool: ...
     # Completion based I/O methods returning Futures prior to 3.7
     if sys.version_info >= (3, 7):
         async def sock_recv(self, sock: socket, nbytes: int) -> bytes: ...

stdlib/asyncio/events.pyi

@@ -417,11 +417,11 @@ class AbstractEventLoop(metaclass=ABCMeta):
     @abstractmethod
     def add_reader(self, fd: FileDescriptorLike, callback: Callable[..., Any], *args: Any) -> None: ...
     @abstractmethod
-    def remove_reader(self, fd: FileDescriptorLike) -> None: ...
+    def remove_reader(self, fd: FileDescriptorLike) -> bool: ...
     @abstractmethod
     def add_writer(self, fd: FileDescriptorLike, callback: Callable[..., Any], *args: Any) -> None: ...
     @abstractmethod
-    def remove_writer(self, fd: FileDescriptorLike) -> None: ...
+    def remove_writer(self, fd: FileDescriptorLike) -> bool: ...
     # Completion based I/O methods returning Futures prior to 3.7
     if sys.version_info >= (3, 7):
         @abstractmethod