HTML API: Add support for HR element.

Adds support for the following HTML elements to the HTML Processor:

 - HR

Previously, this element was not supported and the HTML Processor would bail when encountering
it. Now, with this patch, it will proceed to parse an HTML document when encountering one.

Developed in WordPress/wordpress-develop#5897

Props jonsurrell, dmsnell
Fixes #60283


Built from https://develop.svn.wordpress.org/trunk@57314


git-svn-id: https://core.svn.wordpress.org/trunk@56820 1a063a9b-81f0-0310-95a4-ce76da25c4cd

Author: dmsnell

wp-includes/html-api/class-wp-html-processor.php

@@ -109,7 +109,7 @@
  *  - Media elements: AUDIO, CANVAS, FIGCAPTION, FIGURE, IMG, MAP, PICTURE, VIDEO.
  *  - Paragraph: P.
  *  - Phrasing elements: ABBR, BDI, BDO, CITE, DATA, DEL, DFN, INS, MARK, OUTPUT, Q, SAMP, SUB, SUP, TIME, VAR.
- *  - Sectioning elements: ARTICLE, ASIDE, NAV, SECTION.
+ *  - Sectioning elements: ARTICLE, ASIDE, HR, NAV, SECTION.
  *  - Templating elements: SLOT.
  *  - Text decoration: RUBY.
  *  - Deprecated elements: ACRONYM, BLINK, CENTER, DIR, ISINDEX, MULTICOL, NEXTID, SPACER.
@@ -941,6 +941,17 @@ private function step_in_body() {
 				$this->reconstruct_active_formatting_elements();
 				$this->insert_html_element( $this->state->current_token );
 				return true;
+
+			/*
+			 * > A start tag whose tag name is "hr"
+			 */
+			case '+HR':
+				if ( $this->state->stack_of_open_elements->has_p_in_button_scope() ) {
+					$this->close_a_p_element();
+				}
+				$this->insert_html_element( $this->state->current_token );
+				$this->state->frameset_ok = false;
+				return true;
 		}
 
 		/*
@@ -977,7 +988,6 @@ private function step_in_body() {
 			case 'FRAME':
 			case 'FRAMESET':
 			case 'HEAD':
-			case 'HR':
 			case 'HTML':
 			case 'IFRAME':
 			case 'INPUT':

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.5-alpha-57313';
+$wp_version = '6.5-alpha-57314';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.