Upgrade erusev/parsedown from 1.7.4 to 1.8.0

Update the parsedown dependency to the latest stable release (1.8.0)
which includes security fixes and improved CommonMark compliance.

Update MarkdownParser::blockHeader() to use the 1.8.0 element structure
where handler is now an array with function/argument/destination keys,
and child elements use the 'elements' key directly. This also fixes a
pre-existing bug where header anchor IDs were empty because
sanitize_title_with_dashes() was processing raw Parsedown inline tokens
instead of plain text.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
(cherry picked from commit f698bcb)

Author: 2 people

composer.json

@@ -19,7 +19,7 @@
 	},
 	"require": {
 		"php": ">=8.2",
-		"erusev/parsedown": "~1.7.4",
+		"erusev/parsedown": "~1.8.0",
 		"mustangostang/spyc": "^0.6.3"
 	},
 	"extra": {

inc/class-markdownparser.php

@@ -176,12 +176,17 @@ protected function inlineInternalLink( $result, $parts ) {
 	 */
 	protected function blockHeader( $data ) {
 		$block = parent::blockHeader( $data );
-		$id = sanitize_title_with_dashes( $block['element']['text'] );
+		if ( empty( $block ) ) {
+			return $block;
+		}
+
+		$text = $block['element']['handler']['argument'];
+		$id = sanitize_title_with_dashes( $text );
 
 		// Use a manual ID if provided.
-		if ( preg_match( '/^(.+) ?\{#(.+?)\}$/', $block['element']['text'], $matches ) ) {
+		if ( preg_match( '/^(.+) ?\{#(.+?)\}$/', $text, $matches ) ) {
 			$id = $matches[2];
-			$block['element']['text'] = $matches[1];
+			$block['element']['handler']['argument'] = $matches[1];
 		}
 
 		return [
@@ -192,8 +197,7 @@ protected function blockHeader( $data ) {
 					'id' => $id,
 					'class' => 'header-anchor',
 				],
-				'handler' => 'elements',
-				'text' => [ $block['element'] ],
+				'elements' => [ $block['element'] ],
 			],
 		];
 	}