Add return docblock type

src/Twig/Runtime/IconRuntime.php

@@ -29,7 +29,7 @@ final class IconRuntime implements RuntimeExtensionInterface
      * @param array $options
      * ```
      * $options = [
-     *     'icon'    => (string)  REQUIRED Icon name without trailing `.svg`
+     *     'icon'    => (string)  **REQUIRED** Icon name without trailing `.svg`
      *     'title'   => (?string) Title text to appear on mouse hover
      *     'size'    => (int)     Height and width in px
      *     'colour'  => (string)  Main colour
@@ -37,6 +37,8 @@ final class IconRuntime implements RuntimeExtensionInterface
      *     'classes' => (array)   Additional classes to add to the icon. Not recommended.
      * ]
      * ```
+     *
+     * @return string Processed SVG
      */
     public function renderIcon(array $userOptions): string
     {