zsh/completions: add_cask_options

style shellcheck fixes (in preparation for ubuntu-20.04)

gperf: add to uses_from_macos allowlist

bottle: add `old_checksums` helper function

Correct Formula Cookbook (missing ?)

missing_formula: fix cask installation advice on tap migration

When an installed formula is missing and its source has migrated
to a new tap, Homebrew warns the user about this, saying:

	You can access it again by running:
	  brew tap new-name
	And then you can install it by running:
	  brew cask install new-name

Unfortunately, the "brew cask install" incantation is deprecated
and the advice won't work:

	Error: Calling brew cask install is disabled! Use brew install [--cask] instead.

This alters the advice to use the new "brew install --cask" notation,
fixing the advice presented to the user.

Correct Messaging section:
missing ? in: build.with?("qt5")

Avoid unnecessary downloads in `audit`.

Add a missing backtick on docs Shell Completion page

Merge pull request #10193 from Homebrew/dependabot/bundler/Library/Homebrew/rubocop-performance-1.9.2

build(deps): bump rubocop-performance from 1.9.1 to 1.9.2 in /Library/Homebrew

bottle: check actual bottle block contents when `--keep-old`

cmd/update-report: fix to show new tag

Bumps [rubocop-performance](https://github.com/rubocop-hq/rubocop-performance) from 1.9.1 to 1.9.2.
- [Release notes](https://github.com/rubocop-hq/rubocop-performance/releases)
- [Changelog](https://github.com/rubocop-hq/rubocop-performance/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rubocop-hq/rubocop-performance/compare/v1.9.1...v1.9.2

)

Signed-off-by: dependabot[bot] <support@github.com>

Documentation updates

doctor: disable python symlink message

livecheck: update URL patterns

cleanup: don't do stale check when passing --prune.

utils/ast: cleanup

build(deps): bump rubocop from 1.5.1 to 1.7.0 in /Library/Homebrew

Add more links to the changelog and blog

Co-authored-by: Sam Ford <1584702+samford@users.noreply.github.com>

formula_installer: improve no-bottle error message

This speeds up `--prune` fairly considerably.

Before:
```
$ hyperfine --warmup 3 'brew cleanup --prune=365'
Benchmark #1: brew cleanup --prune=365
  Time (mean ± σ):     33.352 s ±  0.654 s    [User: 21.684 s, System: 6.458 s]
  Range (min … max):   31.901 s … 34.096 s    10 runs
```

After:
```
$ hyperfine --warmup 3 'brew cleanup --prune=365'
Benchmark #1: brew cleanup --prune=365
  Time (mean ± σ):      6.821 s ±  0.186 s    [User: 2.225 s, System: 3.926 s]
  Range (min … max):    6.578 s …  7.178 s    10 runs
```

Closes https://github.com/Homebrew/brew/pull/10177/
Fixes https://github.com/Homebrew/brew/issues/10172