add link to template renderer docs

Author: kpicaza

docs/_sidebar.md

@@ -12,3 +12,4 @@
     * [Console Tool](https://cli.antidotfw.io/)
     * [Logger](https://logger.antidotfw.io/)
     * [Symfony config translator](https://sf-config.antidotfw.io/)
+    * [Template Renderer](https://template.antidotfw.io/)