More RuboCops fixes

Also, clarify where `brew readall` is run.

This stops stuff like `clang=1` from being matched incorrectly.

pr-pull: eliminate another curl call

Delete trailing `;` in Content-Disposition header.

We're setting the basename, so no need to make a curl call to figure out
what it ought to be. This should speed up bottle pulls even more.

utils/github: form encode workflow branch

docs/Releases: various updates.

Update with and based on the release process video I recorded.

`brew style` fixes

Otherwise this is just doing `rubocop` checks.

This is no longer used anywhere.

dev-cmd/pr-pull: fix strategy error

dev-cmd: add pr-automerge

pr-pull: fix to fetch extra-large bottles

Co-Authored-By: Mike McQuaid <mike@mikemcquaid.com>

formula: add on_macos and on_linux

audit whether GitHub prerelease or not

ENV/std: conditionally apply AES-NI workaround

ENV/std: remove space in -isysroot

audit: fix keg_only check

Fix KegOnlyReason property access.