Add missing character (#13922)

src/transformers/tokenization_utils_base.py

@@ -1562,7 +1562,7 @@ class PreTrainedTokenizerBase(SpecialTokensMixin, PushToHubMixin):
             resume_download (:obj:`bool`, `optional`, defaults to :obj:`False`):
                 Whether or not to delete incompletely received files. Attempt to resume the download if such a file
                 exists.
-            proxies (:obj:`Dict[str, str], `optional`):
+            proxies (:obj:`Dict[str, str]`, `optional`):
                 A dictionary of proxy servers to use by protocol or endpoint, e.g., :obj:`{'http': 'foo.bar:3128',
                 'http://hostname': 'foo.bar:4012'}`. The proxies are used on each request.
             use_auth_token (:obj:`str` or `bool`, `optional`):