Update changelog

Author: Taaku18

CHANGELOG.md

@@ -13,6 +13,7 @@ however, insignificant breaking changes do not guarantee a major version bump, s
 - Loading the blocked list with the `?blocked` command takes a long time when the list is large. ([PR #3242](https://github.com/kyb3r/modmail/pull/3242))
 - Reply not being forwarded from DM. (PR [#3239](https://github.com/modmail-dev/modmail/pull/3239))
 - Cleanup imports after removing/unloading a plugin. ([PR #3226](https://github.com/modmail-dev/Modmail/pull/3226))
+- Fixed a syntactic error in the close message when a thread is closed after a certain duration. ([PR #3233](https://github.com/modmail-dev/Modmail/pull/3233))
 
 ### Added
 - `?log key <key>` to retrieve the log link and view a preview using a log key. ([PR #3196](https://github.com/modmail-dev/Modmail/pull/3196))