Rewrite which formula in bash

[hyuraku]

• 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?

---

closes #20750

[MikeMcQuaid]

Looks good so far! Might be worth looking at other shell commands to better match the style.

Are there any additions needed for brew.sh?

[MikeMcQuaid]

Thanks @hyuraku!

[p-linnane]

Actions is having a hard time today.

[Rylan12]

Thanks, @hyuraku!