Changelog: Add info about the websearch option

CHANGELOG.md

@@ -21,6 +21,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Configuration: Add `:instance, autofollowing_nicknames` setting to provide a way to make accounts automatically follow new users that register on the local Pleroma instance.
 - Ability to view remote timelines, with ex. `/api/v1/timelines/public?instance=lain.com` and streams `public:remote` and `public:remote:media`.
 - The site title is now injected as a `title` tag like preloads or metadata.
+- Added a configuration option to use the postgresql `websearch` function for more complicated search queries.
 
 <details>
   <summary>API Changes</summary>