//https://wordpress.stackexchange.com/questions/27234/remove-whitespace-at-the-end-of-posts
function trim_post_trailing_whitespace( $content ) {
	$content = preg_replace("/ /", "☺", $content);
    $content = rtrim($content, "☺");
    $content = rtrim($content);
    $content = preg_replace("/☺/", " ", $content);
    return $content;
}
add_filter( 'the_content', 'trim_post_trailing_whitespace', 0 );