[WebLink] fix types on Link::withAttribute()

Author: nicolas-grekas

Link.php

@@ -46,7 +46,7 @@ class Link implements EvolvableLinkInterface
     private $rel = [];
 
     /**
-     * @var string[]
+     * @var array<string, string|bool|string[]>
      */
     private $attributes = [];
 
@@ -132,6 +132,8 @@ public function withoutRel($rel)
     /**
      * {@inheritdoc}
      *
+     * @param string|bool|string[] $value
+     *
      * @return static
      */
     public function withAttribute($attribute, $value)