Allow references to casks when running uninstall and reinstall

[whoiswillma]

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Allow referencing a cask when running brew uninstall and brew reinstall. If a name cannot be resolved to a formula, then an attempt at resolving a cask is made.

I had difficulty writing tests for brew reinstall <cask> due to an issue with casks in the regular brew test environment. More about that on the Homebrew discourse: https://discourse.brew.sh/t/brew-test-environment-running-cask-commands-from-within-brew-tests/8179

[MikeMcQuaid]

Looking great so far, fantastic work @whoiswillma!

[whoiswillma]

Do you have any suggestions on how to test brew reinstall?

[MikeMcQuaid]

Do you have any suggestions on how to test brew reinstall?

This may scare you a bit but: not really, no. It's pretty hard to test logic for cmd/ files without being really, really slow. If it's possible to extract some logic to another class (e.g. reinstall.rb) we could write unit tests for that. I think it would be 🆗 for this PR to not have tests, given this.

[MikeMcQuaid]

Looking good so far, nice work!

[MikeMcQuaid]

Great work again @whoiswillma!