Multiple bug fixes

【Contents of fixes】
■Support WP5.6 (compatible with jQuery version upgrade)
■【Mac】Fixed a bug that Japanese and European characters may be displayed with different thickness when using some fonts.

The following files have been fixed in this update.
【Fixed files】
comments.php
editor-style-02.css
functions/head.php
functions/ogp.php
pagebuilder/assets/css/pagebuilder.css
style.css

【Added files】
js/jquery.easing.1.4.js