Implement exercise hangman

[junming403]

Fixes #745

Solution based on the work of #1160

Config file lint with tool configlet, shall I keep all the changes in the config?

Ready for review

[cmccandless]

Since this file is supposed to be generated with configlet generate, I'm not comfortable with manually editing it, even to remove inaccurate (to this track) data.

Here are the options I can think of:

• Add a note to this exercise's .meta/HINTS.md that tells users to ignore the part about a 3rd-party framework.
• Leave inaccurate data as-is (least preferable)
• Submit a PR to exercism/problem-specifications to remove the reference to a 3rd-party framework, leaving it to individual tracks to add that information (i.e. C# track does this already)
• Mark this exercise as foregone since there is no builtin FRP framework. There is a precedent for this with the lens-person exercise.
• [Insert other options here]

[junming403]

Thank you for the feedback, I have added a hint about that.

[junming403]

I have updated according to the review, except the part regarding config file. Thank you!

[junming403]

Sorry for the careless mistake, I have fixed them, ready for review. Thank you.

[junming403]

Hi Sir, Would you mind help me review this again? @cmccandless

[cmccandless]

Apologies for the silence.

I've been struggling with whether to include this exercise at all, since we are intentionally ignoring the exercise purpose as stated in its README (FRP). I think for now, we will go ahead and merge it in, with the option to redesign it later if we find a good solution for simulating FRP.

[cmccandless]

Just a couple other minor things that I noticed in my last review. We'll be good to go after these.

[junming403]

Thank you for your review, I have updated the config files.
Is there any other exercises I can help with?