[TASK] Mark OutputFormatter as @internal

This class should only be used for formatting CSS from
within this library. It is not intended to be called
from outside.

CHANGELOG.md

@@ -21,6 +21,7 @@ Please also have a look at our
 
 ### Changed
 
+- Mark `OutputFormatter` as `@internal` (#896)
 - 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/OutputFormat.php

@@ -798,11 +798,15 @@ public function beLenient(): void
         $this->bIgnoreExceptions = true;
     }
 
+    /**
+     * @internal since 8.8.0
+     */
     public function getFormatter(): OutputFormatter
     {
         if ($this->oFormatter === null) {
             $this->oFormatter = new OutputFormatter($this);
         }
+
         return $this->oFormatter;
     }
 

src/OutputFormatter.php

@@ -7,6 +7,9 @@
 use Sabberworm\CSS\Comment\Commentable;
 use Sabberworm\CSS\Parsing\OutputException;
 
+/**
+ * @internal since 8.8.0
+ */
 class OutputFormatter
 {
     /**