Fix Phpstan errros

Author: rcalicdan

src/Contract/ContractParser.php

@@ -1079,4 +1079,4 @@ public static function substituteAliases(TypeNode $node, array $aliases): TypeNo
 
         return $node;
     }
-}
+}

src/Internal/ContractVisitor.php

@@ -27,9 +27,9 @@ public function __construct()
     /**
      * Traverses and transforms AST nodes during entry.
      *
-     * @return array<Node>|int|null
+     * @return array<Node>|null
      */
-    public function enterNode(Node $node): array|int|null
+    public function enterNode(Node $node): ?array
     {
         if ($node instanceof Node\Stmt\Function_
             || $node instanceof Node\Stmt\ClassMethod
@@ -224,4 +224,4 @@ private function extractDestructuringVariables(Node\Expr\List_|Node\Expr\Array_
 
         return $vars;
     }
-}
+}

src/Internal/Visitor/FunctionContractInjector.php

@@ -642,4 +642,4 @@ public function enterNode(Node $n): int|array|null
 
         return $newStmts;
     }
-}
+}