Fix wrong docblock

Author: andreskrey

src/Nodes/NodeTrait.php

@@ -428,7 +428,7 @@ public function hasSingleTagInsideElement($tag)
                 return false;
             }
 
-            /** @var $child DOMNode */
+            /** @var DOMNode $child */
             return !($child->nodeType === XML_TEXT_NODE && !preg_match('/\S$/', $child->getTextContent()));
         });
     }