Add latest version number to changelog

CHANGELOG.md

@@ -5,7 +5,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to
 [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## Unreleased
+## [0.5.9][] - 2022-02-23
 ### Fixed
 - Release notes won't have superfluous line breaks anymore.
 
@@ -306,6 +306,7 @@ when attempting to set a stat to something nonsensical such as
 commands.
 - (Code) Table utilities. Includes functions to operate on tables.
 
+[0.5.9]: <https://github.com/Kumodatsu/CharacterSheet/releases/tag/v0.5.9>
 [0.5.8]: <https://github.com/Kumodatsu/CharacterSheet/releases/tag/v0.5.8>
 [0.5.7]: <https://github.com/Kumodatsu/CharacterSheet/releases/tag/v0.5.7>
 [0.5.6]: <https://github.com/Kumodatsu/CharacterSheet/releases/tag/v0.5.6>