[tqdm] Add return type to tqdm.asyncio.gather (#13839)

stubs/tqdm/tqdm/asyncio.pyi

@@ -81,7 +81,7 @@ class tqdm_asyncio(std_tqdm[_T]):
         nrows: int | None = ...,
         colour: str | None = ...,
         delay: float | None = ...,
-    ): ...
+    ) -> list[_T]: ...
     @overload
     def __init__(
         self,