Add documentation on kind signatures, which ones are displayed, and why

[JordanMartinez]

Fixes #434

I'll have to update the changelog with an entry for this after #436 gets merged.

[thomashoneyman]

I've included a few comments. In general this feels a little long; I wonder if we could trim some of the details or move them into the purs docs documentation instead.

I'm also not totally sold on the 'interesting' vs. 'uninteresting' terminology, though I don't have a better pairing in mind at the moment.

[JordanMartinez]

I've addressed all feedback. I tried making it shorter by removing a few things. How is it now?

[kl0tl]

The example sections feel redundant with the “Interesting kinds are displayed; Uninteresting kinds are not” section. Perhaps we could provide examples when explaining what kinds are uninteresting and then show some interesting kinds as counterexamples?

[JordanMartinez]

Perhaps we could provide examples when explaining what kinds are uninteresting and then show some interesting kinds as counterexamples?

Isn't that what I already do in this PR in the subsections?

[kl0tl]

Yes, but I don’t think it is necessary to rehash what uninteresting kinds are in the “Examples of "uninteresting" kind signatures“ section.

[JordanMartinez]

How are the latest changes?

[JordanMartinez]

@thomashoneyman Thanks for the approval! This has been merged. We can redeploy Pursuit and finally announce v0.14.3