Add support for Idris language

[bmwant]

Description

• Add lexer for Idris programming language
• Ported from sublime plugin tmLanguage

Testing

• Added specs
• Tested with visual/demo examples

[bmwant]

hey @pyrmont, could you take a look?

[pyrmont]

@bmwant Sorry not to have got around to this yet. I'm afraid I haven't had much time to spend on Rouge of late but will try to remedy that soon!

[pyrmont]

This looks really good! Have a couple of comments:

[tancnle]

👋🏼 @bmwant we would love to hear back from you. Is there anything we can help to push this PR forward?

[bmwant]

@tancnle hey, I can recall that I've faced a couple of blocking issues when trying to address these simple at a first glance comments. I cannot remember whether it was related to the Ruby language (as I'm not a Ruby developer per se) or to the implementation details of the lexer itself (regex lexers are trickier to implement).
If that's something related to the language I'll reach back here with my questions/clarifications, but in case it's the latter (and I suspect it's more likely) I just don't have enough mental energy to face again that horrible process of debugging 😢

[tancnle]

@bmwant Thank you for getting back to me. I am happy to lend a hand with the latter. Idris is an interesting language and this addition to Rouge will definitely improve the exp. for our developers.

I will review those comments from @pyrmont and help to address them in the meantime.

[nickdrozd]

Would it be possible to add a simpler version of Idris highlighting first, and then polish it later? I've been using Haskell highlighting for my Idris code blocks, and that looks terrible, so for me any real Idris support at all would be an improvement.

(I'm afraid I don't have anything concrete to offer in terms of this PR. This is just a suggestion to take the simpler-sooner route.)

[tancnle]

@bmwant I have pushed some changes to address the feedback from @pyrmont. Could you please have another look? 🙏🏼

[tancnle]

@bmwant In the spirit of iteration, I will merge this change 👍🏼. Please let me know if you have any concerns and/or raise another PR to address them. Again, thank a lot for your hard work on this PR 🙇🏼