regenerate sample config

docs/sample_config.yaml

@@ -1103,9 +1103,9 @@ password_config:
 #
 # 'search_all_users' defines whether to search all users visible to your HS
 # when searching the user directory, rather than limiting to users visible
-# in public rooms.  Defaults to false.  If you set it True, you'll have to run
-# UPDATE user_directory_stream_pos SET stream_id = NULL;
-# on your database to tell it to rebuild the user_directory search indexes.
+# in public rooms.  Defaults to false.  If you set it True, you'll have to
+# rebuild the user_directory search indexes, see
+# https://github.com/matrix-org/synapse/blob/master/docs/user_directory.md
 #
 #user_directory:
 #  enabled: true