SportsPress: Replace line breaks with `\n` in iCal feeds

sportspress_fix_ical_line_breaks.php

<?php

add_filter('posts_results', function($posts, $query) {
	if (empty($_GET['feed']) || $_GET['feed'] !== 'sp-ical') {
		return $posts;
	}
	foreach ($posts as &$post) {
		$post->post_content = preg_replace("/\r?\n/", "\\n", $post->post_content);
	}
	return $posts;
}, 10, 2);