[requests] Specify that adapters.HTTPAdapter.close() returns None

Author: mharding-hpe

stubs/requests/requests/adapters.pyi

@@ -96,7 +96,7 @@ class HTTPAdapter(BaseAdapter):
     ) -> ConnectionPool: ...
     @deprecated("Use get_connection_with_tls_context() instead.")
     def get_connection(self, url: _Uri, proxies: Mapping[str, str] | None = None) -> ConnectionPool: ...
-    def close(self): ...
+    def close(self) -> None: ...
     def request_url(self, request, proxies): ...
     def add_headers(self, request, **kwargs): ...
     def proxy_headers(self, proxy): ...