Formatter: Parens added around function with wildcard argument

[glennsl]

Very minor regression in rescript@11:

"foo"->Js.log(_)

will be formatted to

"foo"->(Js.log(_))

Doesn't cause any issues outside of just being inconsistent and annoying though.

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[glennsl]

Still present in 11.1.3 and 12.0.0-alpha.1 on the playground.

[glennsl]

Presumably fixed by #7370