Add a note to allow_uncategorized_topics description

Author: nlalonde

config/locales/server.en.yml

@@ -452,7 +452,7 @@ en:
     max_topic_title_length: "Maximum topic title length in characters"
     min_private_message_title_length: "Minimum title length for a private message in characters"
     min_search_term_length: "Minimum search term length in characters"
-    allow_uncategorized_topics: "Allow topics to be created without a category"
+    allow_uncategorized_topics: "Allow topics to be created without a category. NOTE: After changing this setting, all clients will need to reload their browsers for the change to take effect."
     allow_duplicate_topic_titles: "Allow topics with identical titles"
     unique_posts_mins: "How many minutes before a user can make a post with the same content again"
     enforce_global_nicknames: "Enforce global nickname uniqueness (WARNING: only change this during initial setup)"