Always a good idea to quote command substitution.

test-bot: separate tap/core no formula handling.

`e.tap` calls the tap method which wants a block on
`FormulaUnavailableError` so the previous approach is 👎.

test-bot: handle missing tap in exception.

Handle the case where a `FormulaUnavailableError` does not contain a tap
reference so fall back to `CoreTap` in this case.

xcode: die unless Xcode/CLT up-to-date on prerelease macOS

test-bot: put exception, retry on missing formula.

Better use the abstraction layer so e.g. Linux could have similarly
fatal checks for these things.

This will be useful in debugging (and recovering from) the situation
where sometimes formulae can't be found when specifying multiple on the
command-line.

update-report: also link docs, completions.

minor typo

Fixed minor typo -- missing preposition.

test-bot: tweak cleaning behaviour again.

Always run `git clean -ffdx` on HOMEBREW_REPOSITORY. Also, ensure that
if we can't find a formula that's logged.

test-bot: git clean less in cleanup_*.

These are more files in the HOMEBREW_REPOSITORY that we want to link to
the HOMEBREW_PREFIX.

Pull more logic into the more generic `link_src_dst_dirs` to be used to
do more linkage.

There's edge-cases which is breaking tap CI.

Add `cask_files` method to `Tap` class.

Catch system libressl in openssl audit as well

test-bot: never cleanup homebrew/core.

doc/Interesting-Taps-&-Branches: rename to Interesting-Taps-&-Forks

Otherwise weird things happen and formulae can't be found.

Fix shell profile

Update the description to reflect that we may be talking about either crypto library and neither is okay. :)

This document lists Tigerbrew and Linuxbrew as interesting forks, not
branches (they used to be "Interesting Branches (aka forks)" but that
changed in b7455469), so "Interesting Taps & Branches" is a more fitting
title.

The term "branches" is also presumably confusing to folks with a shallow
understanding of GitHub and/or git who may not realize how GitHub forks
and git branches are related.

--env: support more shells, allow explicit shell selection

test-bot: use UPSTREAM_BOTTLE_KEEP_OLD.

This is set by Jenkins to indicate a downstream bottle upload job needs
to use `brew bottle --keep-old`.

bottle: revert --keep-old changes.

update-report: add newline if preinstall updated.

test-bot: cleanup all repositories.

bump-formula-pr: audit formula before opening PR

note that it was made opt-in not opt-out

tap_constants: allow formulae to have @ in name.

This reverts commit 5e9bb877.

This reverts commit ec143749.