New command: hub gist

Add git pr show --format=... flag

Add hub api --obey-ratelimit flag

hub help: support compressed man pages

Add hub release download --include=PATTERN flag

hub help: Enable hub help --web <command>

hub release: Retry attaching release assets on 5xx server errors

hub pr checkout fixes

• handle case when the PR given matches the current branch
• avoid overriding existing branch merge config

hub release: Fail fast when attempting to attach unavailable files

Honor HTTPS_PROXY, NO_PROXY environment variables

Strip "co-authored-by" lines when populating PR body from git log

git compatibility: have hub <cmd> --help open the man page

hub fork bash completion improvements

hub pr fish completion improvements