fix: Update output for brew_install and cleanup feat: multi suggestions for formulas

[pyrrolizin]

The output of brew install, if no suitable formula was found, has changed. Before it was an error, now it is a warning with suggestions which formula could be meant.

The function to find the most similar formula doesn't work anymore (_get_formulas()), because the path in brew and the logic has changed. But this is not necessary anymore, because brew provides the matching match.

Example output:

$ brew install gitt
Warning: No available formula with the name "gitt". Did you mean git, gitg or gist?
==> Searching for similarly named formulae...
These similarly named formulae were found:
git-test            git-town            gitter-cli          git
git-tf              git-tracker         moz-git-tools       gitg
git-tig             git-trim            sagittarius-scheme  gist
To install one of them, run (for example):
  brew install git-test
==> Searching for a previously deleted formula (in the last month)...
Error: No previously deleted formula found.
==> Searching taps on GitHub...
Error: No formulae found in taps.

The formulas can contain special characters. That is why the regex has been extended.

Rule brew_install and test test_brew_install are adjusted and cleaned up.

closes #1299

[scorphus]

Nice catch! Thank you.

Please consider my comment below.

[pyrrolizin]

okay, the implementation was easier than expected.
@scorphus multi suggestions added (incl. tests).

[scorphus]

Thanks for your contribution, @pyrrolizin! Kudos for the complete patch 👍