Code control

Hi there,

I was thinking of trying to use the code control in my theme and I got it into the customizer where I want and so now I have questions.

1. I see you have this in the control example

	'choices'     => array(
		'language' => 'css',
	),

How can I add other languages like php or html?

2. I did change the language to php and inserted <?php echo '<p>Hello World</p>' ;?> to see what would happen and I got the following msg from wp 4.9

There are 2 errors which must be fixed before you can save. and there is a little line under the opening < and closing >

So exactly how does one add multiple languages to the code control and how does php have to be inserted.

Thanks