Prepare for WordPress 5.5 comment type change

Author: dshanske

includes/class-linkbacks-handler.php

@@ -204,7 +204,8 @@ public static function enhance( $commentdata, $comment = array(), $commentarr =
 		// remove "webmention" comment-type if $type is "reply"
 		if ( isset( $commentdata['comment_meta']['semantic_linkbacks_type'] ) ) {
 			if ( in_array( $commentdata['comment_meta']['semantic_linkbacks_type'], apply_filters( 'semantic_linkbacks_comment_types', array( 'reply' ) ), true ) ) {
-				$commentdata['comment_type'] = '';
+				// https://core.trac.wordpress.org/ticket/49236 - As of WP5.5, comment will be the default comment type, not empty.
+				$commentdata['comment_type'] = version_compare( get_bloginfo( 'version'), '5.5', '>=' ) ) ? 'comment' : '';
 			}
 		}