A very simple shortcode to clear content following aligned images.

mrw-clear-shortcode.php

<?php
/*
Plugin Name: Clear Aligned Content Shortcode
Description: A way to ensure floated images in page content don't wrap. Use [clear] in editor to push following content below any aligned images.
Author: Mark Root-Wiley
Version: 1.0
Author URI: https://MRWweb.com
Plugin URI: https://gist.githubusercontent.com/mrwweb/f627f3fe407a64293f6a99d701526b94/raw/c0e23d2f5b0252332e4f7c549a2990b4c944cfe1/mrw-clear-shortcode.php

USAGE:
 
Place "[clear]" on own line in WordPress editor.
 
Any content on following lines will appear below any previous aligned images.
 
 */

add_shortcode( 'clear', 'mrw_clear_shortcode' );

function mrw_clear_shortcode() {
	  return '<span style="display:block !important; clear:both !important; width: 100% !important; height: 1px !important; border: 0 !important; background: transparent !important;"></span>';
}