TODO

Parse review files
- Create parser
- Create include_str!() based unit-tests for expected comments
  - Test invalid spans (span that does not have a comment that terminates it and another span starts)
Wire up comment uploading to GH
Inspect response error codes and body
Fix bug where line and start_line are being set instead of position
- Check if start_position is accepted
- Add test for trying to comment on a hunk start
Figure out how to calculate line for diffs w/ changes on both sides
Add test for comment at end of review file
Prohibit cross hunk spanned comments
Support review-level comments at top of review file
Manual test that comments on a changed file work
Support approve/rejecting PRs
- Need some kind of meta syntax (like go's //+)
  - Think about if it could be generalized to comment threads
Support updating a PR's review file, but ask for confirmation if review file has been modified and not submitted yet
- Maybe even check mtime between review file and submission time?
Support parsing github url from stdin
Save commit hash of downloaded review file
Support [...] snipping
Support comment threads. Maybe do nested '>'s like actual mailing lists?

Thoughts

Make a comment spanned by inserting a whitespace line before the start of the span
- To compose with back-to-back spanned comments, the latter comment must be assumed to be a single line comment. Otherwise, using a single spanned comment always makes the next comment a span. This kinda actually makes sense conceptually too cuz if the user actually wants back-to-back spans then they should've just used a single, larger span.
Need to be careful to prohibit a spanned comment over multiple files