Make the changelog entry more specific

Author: oliverklee

CHANGELOG.md

@@ -47,7 +47,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 
 ### Fixed
 
-- Fix type errors in strict mode (#664)
+- Fix type errors in PHP strict mode (#664)
 - Fix comment parsing to support multiple comments (#672)
 - Fix undefined local variable in `CalcFunction::parse()` (#593)
 - Fix PHP notice caused by parsing invalid color values having less than 6 characters (#485)