Support adding/editing PR Review Comments

[dgrisham]

Is your feature request related to a problem? Please describe.
Large pull request reviews in Github can be a pain, as the UI can be unusably slow. The ability to do this from the command line would be extremely useful. gh-dash supports viewing PR comments, but not adding/editing (as far as I've seen).

Describe the solution you'd like
It would be great to be able to review a PR through gh-dash, or at least for it to facilitate this feature that a text editor can integrate with. There are separate projects that achieve this for specific editors, like octo.nvim or VS Code's Github Pull Request plugin, but having this in gh-dash would be very useful.

Describe alternatives you've considered
From what I can tell, my alternative options are to switch text editors (I use Kakoune) or to hack together a solution myself. gh alone does not provide any such support.

Additional context
I would love to be able to draft additional comments/a full review locally that I can submit to GH once finished. These comments would somehow be viewable from gh-dash alongside the line(s) they're referencing.

Here are Github's relevant docs: https://docs.github.com/en/rest/pulls/comments