This commit improves behavior and error handling for pr commands when
run unattached to a tty.
- error if pr create and no -t/-f
- error if pr create and -w
- machine readable pr list
- machine readable pr view
- various cleanup of informational messages
this commit add very basic non-interactive PR reviewing. You can either
review the "current" or a passed PR (number or URL) as approved, changes
requested, or commented via CLI flags.