GeSHi highlight icon bug

[respencer]

I noticed yesterday that a bash file I had in a code block has a broken icon:

<code bash updpkg>

Looking at the HTML I saw this for the class:

class="mediafile mf_"

It should have been:

class="mediafile mf_bash"

Looking at the code I see that the class name is being determined by the file extension:

dokuwiki/inc/parser/xhtml.php

Lines 654 to 666 in a6016e3

	public function _highlight($type, $text, $language = null, $filename = null, $options = null)
	{
	global $ID;
	global $lang;
	global $INPUT;
	$language = preg_replace(PREG_PATTERN_VALID_LANGUAGE, '', $language ?? '');
	if ($filename) {
	// add icon
	[$ext] = mimetype($filename, false);
	$class = preg_replace('/[^_\-a-z0-9]+/i', '_', $ext);
	$class = 'mediafile mf_' . $class;

Files don't always have extensions, especially on Unix like systems. If there is no extension, the code should fallback to using the language to determine the correct icon instead of failing with "mf_" as the result.