Add remaining instances for Comonad transformers

[skeate]

Description of the change

Adds ComonadAsk, ComonadEnv, and ComonadTraced instances for StoreT, EnvT, and TracedT

Closes #35

---

Checklist:

• [x] Added the change to the changelog's "Unreleased" section with a reference to this PR (e.g. "- Made a change (#0000)")
• [x] Linked any existing issues or proposals that this pull request should close
• [x] Updated or added relevant documentation
• [x] Added a test for the contribution (if applicable)

[JordanMartinez]

:ping_pong: @garyb

[garyb]

I did take a look at this, but I don't feel qualified to approve it, since I'm not that familiar with comonad patterns. Perhaps @MonoidMusician or @LiamGoodacre could chime in, I think they're more theorypilled than me? :wink:

[garyb]

Yup, looks good to me! It’s doing the “obvious” thing, which is just the opposite of the usual monadic constructions.

Ah okay. I did once implement some comonad stuff and it seemed way too trivial to be correct. I asked someone and they weren't sure if it was right either. :smile:

[MonoidMusician]

Yeah, this is just lifting instances like ask = lift <<< ask in the monadic work, but it's ask = ask <<< lower here :)

[MonoidMusician]

Are we good to merge this btw?