completions/zsh: add --pull-reques to search

build(deps-dev): bump html-proofer from 3.18.2 to 3.18.5 in /docs

utils/ast: add `stanza_text` helper function

formula_installer: tweak bottle error message

Bumps [html-proofer](https://github.com/gjtorikian/html-proofer) from 3.18.2 to 3.18.5.
- [Release notes](https://github.com/gjtorikian/html-proofer/releases)
- [Commits](https://github.com/gjtorikian/html-proofer/compare/v3.18.2...v3.18.5

)

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

superenv: filter out /usr/local on ARM if necessary

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 ?)

Follow up to #10183.

This improves the error message displayed when `formula.pour_bottle?` is
false.

Before:

    ❯ brew install python@3.8
    Error: python@3.8: no bottle available!
    The bottle needs the Apple Command Line Tools to be installed.
      You can install them, if desired, with:
        xcode-select --install
    You can try to install from source with e.g.
      brew install --build-from-source python@3.8
    Please note building from source is unsupported. You will encounter build
    failures with some formulae. If you experience any issues please create pull
    requests instead of asking for help on Homebrew's GitHub, Twitter or any other
    official channels.

After:

    ❯ brew install python@3.8
    Error: python@3.8: the bottle needs the Apple Command Line Tools to be installed.
      You can install them, if desired, with:
        xcode-select --install
    You can try to install from source with e.g.
      brew install --build-from-source python@3.8
    Please note building from source is unsupported. You will encounter build
    failures with some formulae. If you experience any issues please create pull
    requests instead of asking for help on Homebrew's GitHub, Twitter or any other
    official channels.

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