Fix link for language_code setting.

I forgot sphinx link formatting.

Author: tim-schilling

docs/configuration.rst

@@ -158,9 +158,9 @@ Toolbar options
   render the toolbar in a different language than what the application is
   rendered in. For example, if you wish to use English for development,
   but want to render your application in French, you would set this to
-  ``"en-us"`` and (``LANGUAGE_CODE``)[https://docs.djangoproject.com/en/stable/ref/settings/#std-setting-LANGUAGE_CODE]
-  to ``"fr"``.
+  ``"en-us"`` and `settings.LANGUAGE_CODE`_ to ``"fr"``.
 
+.. _settings.LANGUAGE_CODE: https://docs.djangoproject.com/en/stable/ref/settings/#std-setting-LANGUAGE_CODE
 
 Panel options
 ~~~~~~~~~~~~~