Mention bash completion improvements

Author: danielbachhuber

_posts/2016-10-25-version-0.25.0.md

@@ -104,6 +104,7 @@ Framework enhancements:
 * Support passing arguments to `WP_CLI::do_hook()` [[#3470](https://github.com/wp-cli/wp-cli/pull/3470)].
 * Logs the current alias when executing an alias group [[#3471](https://github.com/wp-cli/wp-cli/pull/3471)].
 * Only checks `options` for a positional argument when a value is present [[#3481](https://github.com/wp-cli/wp-cli/pull/3481)].
+* Variety of bash completion improvements [[#3490](https://github.com/wp-cli/wp-cli/pull/3490), [#3491](https://github.com/wp-cli/wp-cli/pull/3491), [#3492](https://github.com/wp-cli/wp-cli/pull/3492)].
 
 Bug fixes across the board: