dev-cmd/tap-new: add Brewfile documentation to readme template

[jasonkarns]

It would be helpful for taps to document how they are to be used with Brewfile.

Adding documentation for formulae installation to the generated tap readme would help ensure that new taps have this helpful documentation in their repos from the start.

This is primarily a follow-up to Homebrew/homebrew-cask-fonts#9359 which itself was opened after I spent a significant amount of time trying to figure out how to get a font installed as part of my Brewfile.

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew style with your changes locally?
• Have you successfully run brew typecheck with your changes locally?
• Have you successfully run brew tests with your changes locally?

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[MikeMcQuaid]

I like this idea, thanks @jasonkarns.

@Homebrew/maintainers any objections?

[jasonkarns]

Good suggested changes @MikeMcQuaid . I'll update the cask-fonts tap PR to match.

[jasonkarns]

Quick aside question: I haven't frequently made changes to brew itself (it's been a long while).

The PR template requests running brew style, brew typecheck and brew tests. But it's not clear if these are expected to work somehow within the context of a Homebrew/brew working copy, or if they only run against the "installed" version of homebrew. Does brew magically detect it's in a clone of brew itself and run against the current working copy? Or do I need to go to /usr/local/Homebrew | /opt/homebrew and check out my branch to run these commands?

(And is this already clarified somewhere that I should have noticed?)

[MikeMcQuaid]

if they only run against the "installed" version of homebrew.

This 👍🏻

Or do I need to go to /usr/local/Homebrew | /opt/homebrew and check out my branch to run these commands?

This 👍🏻