• 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?

Formulae can execute arbitrary Ruby code when being loaded. In
particular, they can print to stdout with methods like puts. This can
break the parsing of output of commands like brew info --json=v2.

Let's fix that by capturing the output to stdout, and then printing
those messages to stderr instead (using opoo to try to discourage
formula authors from doing this).