update changelog

Add missing changelog entry for tailwindlabs#13806

Author: RobinMalfait

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Use `length` data type for `background-size` instead of `background-position` ([#13771](https://github.com/tailwindlabs/tailwindcss/pull/13771))
 - Support negative values for `{col,row}-{start,end}` utilities ([#13780](https://github.com/tailwindlabs/tailwindcss/pull/13780))
 - Use long form `<length> | <percentage>` syntax for properties ([#13660](https://github.com/tailwindlabs/tailwindcss/pull/13660))
+- Fix background position value of `bg-right-top`, `bg-right-bottom`, `bg-left-bottom` and `bg-left-top` ([#13806](https://github.com/tailwindlabs/tailwindcss/pull/13806))
 
 ### Added