Add PonyLang mode in Extra langs

[rajatvig]

This adds support for the Pony Language http://www.ponylang.org/

[robbyoconnor]

You may wanna close this and resubmit it against a topic branch

[rajatvig]

@robbyoconnor which branch do I resubmit it against? Any document I can look at?

[robbyoconnor]

You just make a new branch and do it against develop, this is quite clear (at least I think it is)..to be clear I meant that you should use a topic branch. Because anything you push to this branch will be reflected in this PR ;) Which means until this is merged, you're stuck at an older version....and if you wanan contribute another PR...you'll need to use a topic branch AND remove a commit via an interactive rebase ;)

[rajatvig]

@robbyoconnor I get what you're saying. For the next PR, I'll use a topic branch to avoid getting stuck.

[TheBB]

Thanks, but #5663 seems much more complete so I will roll with that.