Merge branch 'phpDocumentor:6.x' into fix-standard-tag-factory-2

Author: mspirkov

src/DocBlock/StandardTagFactory.php

@@ -162,6 +162,7 @@ public static function createInstance(FqsenResolver $fqsenResolver): self
         $tagFactory->registerTagHandler('property-read', $phpstanTagFactory);
         $tagFactory->registerTagHandler('property-write', $phpstanTagFactory);
         $tagFactory->registerTagHandler('method', $phpstanTagFactory);
+        $tagFactory->registerTagHandler('mixin', $phpstanTagFactory);
         $tagFactory->registerTagHandler('extends', $phpstanTagFactory);
         $tagFactory->registerTagHandler('implements', $phpstanTagFactory);
         $tagFactory->registerTagHandler('template', $phpstanTagFactory);