Update src/zarr/api/asynchronous.py

Co-authored-by: Joe Hamman <[email protected]>

Author: d-v-b

src/zarr/api/asynchronous.py

@@ -697,7 +697,6 @@ async def create_group(
     if zarr_format is None:
         zarr_format = _default_zarr_version()
 
-    # TODO: fix this when modes make sense. It should be `w` for overwriting, `w-` otherwise
     mode: Literal["a"] = "a"
 
     store_path = await make_store_path(store, path=path, mode=mode, storage_options=storage_options)