Rename ManagedStyle to PossiblyUpdatedStyle and add documentation

src/Spout/Writer/Common/Manager/Style/PossiblyUpdatedStyle.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace Box\Spout\Writer\Common\Manager\Style;
+
+use Box\Spout\Common\Entity\Style\Style;
+
+/**
+ * Class PossiblyUpdatedStyle
+ * Indicates if style is updated.
+ * It allow to know if style registration must be done.
+ */
+class PossiblyUpdatedStyle
+{
+    private $style;
+    private $isUpdated;
+
+    public function __construct(Style $style, bool $isUpdated)
+    {
+        $this->style = $style;
+        $this->isUpdated = $isUpdated;
+    }
+
+    public function getStyle() : Style
+    {
+        return $this->style;
+    }
+
+    public function isUpdated() : bool
+    {
+        return $this->isUpdated;
+    }
+}