[1.0] Use BetterNodeFinder::resolveNextNode() on DowngradeNegativeStr…

…ingOffsetToStrlenRector (#59)

* [V1] Use BetterNodeFinder::resolveNextNode() on DowngradeNegativeStringOffsetToStrlenRector

* Update composer.json

rules/DowngradePhp71/Rector/String_/DowngradeNegativeStringOffsetToStrlenRector.php

@@ -69,7 +69,7 @@ public function refactor(Node $node): ?Node
     private function processForStringOrVariableOrProperty(
         String_ | Variable | PropertyFetch | StaticPropertyFetch $expr
     ): ?Expr {
-        $nextNode = $expr->getAttribute(AttributeKey::NEXT_NODE);
+        $nextNode = $this->betterNodeFinder->resolveNextNode($expr);
         if (! $nextNode instanceof UnaryMinus) {
             return null;
         }