Fix phan errors

Signed-off-by: Jack Cherng <[email protected]>

Author: jfcherng

src/Renderer/Html/LineRenderer/Char.php

@@ -13,6 +13,8 @@ final class Char extends AbstractLineRenderer
 {
     /**
      * {@inheritdoc}
+     *
+     * @return static
      */
     public function render(MbString $mbOld, MbString $mbNew): LineRendererInterface
     {

src/Renderer/Html/LineRenderer/Line.php

@@ -11,6 +11,8 @@ final class Line extends AbstractLineRenderer
 {
     /**
      * {@inheritdoc}
+     *
+     * @return static
      */
     public function render(MbString $mbOld, MbString $mbNew): LineRendererInterface
     {

src/Renderer/Html/LineRenderer/None.php

@@ -10,6 +10,8 @@ final class None extends AbstractLineRenderer
 {
     /**
      * {@inheritdoc}
+     *
+     * @return static
      */
     public function render(MbString $mbOld, MbString $mbNew): LineRendererInterface
     {

src/Renderer/Html/LineRenderer/Word.php

@@ -13,6 +13,8 @@ final class Word extends AbstractLineRenderer
 {
     /**
      * {@inheritdoc}
+     *
+     * @return static
      */
     public function render(MbString $mbOld, MbString $mbNew): LineRendererInterface
     {