formula: ensure HOMEBREW_PREFIX/bin in test PATH.

formula: build dependencies are never missing.

Only likely to kick in when environment filtering is enabled.

Otherwise we need to tediously add a dramatic number of PATHs to tests
or recurse through the runtime formulae dependencies and add all them.

CC @ilovezfs

If the formula is already installed and they've been removed: that's ok.

Fixes #2625.

replace_text_in_files: Regex match is greedy

audit: fix full versioned alias name resolution in taps

Use scoped RSpec matchers.

Support GPG (signed data) container in Homebrew Cask

Fix implicit conversion of nil into string error

cask manpage: Fix section header link for Environment

Remove `to_s` from some `Pathname`s.

The regex matches the longest possible string. Order does not matter.

This fixes an issue where audit would prompt for the creation
of an already existing versioned alias while at the same time
declaring the existing alias invalid.

Display formula conflict reasons

audit: Port audit_homepage method to rubocop and add tests

audit: Detect multiline and interpolated strings in formula desc cop

bin/brew: don't set blank HOMEBREW_* variables.

When creating the necessary HOMEBREW_* variables ensure that they aren't
set if their value would be empty.

docs.brew.sh: use SCSS.

audit: fix dependency option detection.

rubocop: don't always care about module length.

More environment filtering tweaks

audit: more checks for versioned aliases.

Allow --interactive to access HOME

keg: skip opt versioned aliases for devel/head.

Import style changes from:
https://github.com/Homebrew/homebrew.github.io/pull/166

Update to venv.pip_install_and_link in doc