docs: remove doubled word in docstring (#209)

Co-authored-by: Tres Seaver <[email protected]>

Author: chie8842

google/cloud/storage/client.py

@@ -545,7 +545,7 @@ def download_blob_to_file(self, blob_or_uri, file_obj, start=None, end=None):
                 (Optional) The last byte in a range to be downloaded.
 
         Examples:
-            Download a blob using using a blob resource.
+            Download a blob using a blob resource.
 
             >>> from google.cloud import storage
             >>> client = storage.Client()