FIX: Better HTML decoding support

See further:
- https://developer.wordpress.org/reference/functions/wp_specialchars_decode/
- https://meta.discourse.org/t/ampersands-getting-over-escaped-going-from-wordpress-to-discourse/300004/7?u=angus

lib/discourse-publish.php

@@ -846,7 +846,7 @@ protected function get_excluded_tag_slugs() {
 	 * @return string
 	 */
 	protected function sanitize_title( $title ) {
-		return wp_specialchars_decode( wp_strip_all_tags( $title ) );
+		return html_entity_decode( wp_strip_all_tags( $title ), ENT_COMPAT, 'UTF-8' );
 	}
 
 	/**

tests/phpunit/test-discourse-publish.php

@@ -858,8 +858,8 @@ public function test_force_publish_max_age_prevents_older_posts_from_being_publi
    * Test that HTML entities are converted to their special characters.
    */
   public function test_conversion_of_html_entities_in_title() {
-		$title_with_entities = 'Title with &';
-		$title_with_decoded_entities = 'Title with &';
+		$title_with_entities = 'Title with & and –';
+		$title_with_decoded_entities = 'Title with & and –';
 		self::$post_atts['post_title'] = $title_with_entities;
 
 		$response         = $this->build_response( 'success' );