[TASK] Mark Selector::isValid() as @internal

Author: oliverklee

CHANGELOG.md

@@ -21,6 +21,7 @@ Please also have a look at our
 
 ### Changed
 
+- Mark `Selector::isValid()` as `@internal` (#1037)
 - Mark parsing-related methods of most CSS elements as `@internal` (#908)
 - Mark `OutputFormat::nextLevel()` as `@internal` (#901)
 - Only allow `string` for some `OutputFormat` properties (#885)

src/Property/Selector.php

@@ -78,6 +78,8 @@ class Selector
      * @param string $selector
      *
      * @return bool
+     *
+     * @internal since V8.8.0
      */
     public static function isValid($selector)
     {