Fix code style issues

Author: colinodell

src/Data.php

@@ -14,6 +14,9 @@
 use RuntimeException;
 use ArrayAccess;
 
+/**
+ * @implements ArrayAccess<string, mixed>
+ */
 class Data implements DataInterface, ArrayAccess
 {
     /**
@@ -247,6 +250,8 @@ public function offsetGet($key)
 
     /**
      * {@inheritdoc}
+     *
+     * @param string $key
      */
     public function offsetSet($key, $value)
     {
@@ -260,5 +265,4 @@ public function offsetUnset($key)
     {
         $this->remove($key);
     }
-
 }

tests/DataTest.php

@@ -248,7 +248,7 @@ public function testOffsetGet()
 
     public function testOffsetSet()
     {
-        $data = new Data;
+        $data = new Data();
 
         $this->assertNull($data['a']);
         $this->assertNull($data['b.c']);