Adds note on possibly redundant condition in FsspecStore.delete_dir()

Author: carshadi

src/zarr/storage/_fsspec.py

@@ -273,6 +273,7 @@ async def delete_dir(self, prefix: str) -> None:
 
         path_to_delete = _dereference_path(self.path, prefix)
 
+        # this is probably the same condition as `if self.fs.async_impl`
         if hasattr(self.fs, "_rm") and inspect.iscoroutinefunction(self.fs._rm):
             with suppress(self.allowed_exceptions):
                 await self.fs._rm(path_to_delete, recursive=True)