Define template type on Result::getNextResult() return

Author: trowski

src/Result.php

@@ -19,8 +19,10 @@ public function fetchRow(): ?array;
     /**
      * Resolves with a new instance of Result if another result is available after this result. Resolves with null if
      * no further results are available.
+     *
+     * @return Result<TFieldValue>|null
      */
-    public function getNextResult(): ?Result;
+    public function getNextResult(): ?self;
 
     /**
      * Returns the number of rows affected or returned by the query if applicable or null if the number of rows is