minor #3301 Remove extra Mardown word in classname (XenoX)

This PR was merged into the 3.x branch.

Discussion
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Remove extra Mardown word in classname

Commits
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e76bd98a Remove extra Mardown word in classname

doc/filters/html_to_markdown.rst

@@ -43,7 +43,7 @@ You can also use the filter on an included file:
     Then, use the ``twig/extra-bundle`` on Symfony projects or add the extension
     explictly on the Twig environment::
 
-        use Twig\Extra\Markdown\MarkdownMarkdownExtension;
+        use Twig\Extra\Markdown\MarkdownExtension;
 
         $twig = new \Twig\Environment(...);
         $twig->addExtension(new MarkdownExtension());

doc/filters/markdown_to_html.rst

@@ -42,7 +42,7 @@ You can also use the filter on an included file:
     Then, use the ``twig/extra-bundle`` on Symfony projects or add the extension
     explictly on the Twig environment::
 
-        use Twig\Extra\Markdown\MarkdownMarkdownExtension;
+        use Twig\Extra\Markdown\MarkdownExtension;
 
         $twig = new \Twig\Environment(...);
         $twig->addExtension(new MarkdownExtension());