Adding page builder functions and correcting wording

【Contents of modification】
■Added an option to the page builder “Tabs” to make the top tab open when viewed on a smartphone.
■Fixed a mistake in the tag description.
■Fixed an error in the name of the widget.
■Fixed an error in the recommended size of images in the category edit screen.

The following are the files that have been modified for this update.
【Corrected files】
・functions/category.php
・pagebuilder/pagebuilder.php
・pagebuilder/assets/admin/css/admin.css
・pagebuilder/modules/tab.php
・language/ja.po
・language/ja.mo
・header.php
・style.css