Menus: Remove an extra space in the `<ul>` tag in `Walker_Nav_Menu::start_lvl()`.

Fixes #42289.
Built from https://develop.svn.wordpress.org/trunk@41955


git-svn-id: http://core.svn.wordpress.org/trunk@41789 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-walker-nav-menu.php

@@ -72,7 +72,7 @@ class Walker_Nav_Menu extends Walker {
 		$class_names = join( ' ', apply_filters( 'nav_menu_submenu_css_class', $classes, $args, $depth ) );
 		$class_names = $class_names ? ' class="' . esc_attr( $class_names ) . '"' : '';
 
-		$output .= "{$n}{$indent}<ul $class_names>{$n}";
+		$output .= "{$n}{$indent}<ul$class_names>{$n}";
 	}
 
 	/**

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-beta3-41954';
+$wp_version = '4.9-beta3-41955';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.