Allowing a user to toggle showing the coding language in a screenshot

[allister-grange]

This is for the issue #1399. As you can see in the images below, you can now toggle "Display Language" so that you can see what language the code is written in for the screenshot.

I was unsure as to whether this should be on by default, to be on the safe side I have defaulted it to "false".

Please let me know if anything is amiss.