Fix missing parentheses on async inside for..of

[fisker]

Description

Fixes #10777

Checklist

• I’ve added tests to confirm my change works.
• (If changing the API or CLI) I’ve documented the changes I’ve made (in the docs/ directory).
• (If the change is user-facing) I’ve added my changes to changelog_unreleased/*/XXXX.md file following changelog_unreleased/TEMPLATE.md.
• I’ve read the contributing guidelines.

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[thorn0]

Strictly speaking, the parens aren't needed in for await (async of []);, but Babel can't parse it without them.

[sosukesuzuki]

@thorn0 Has it been reported to babel/babel or fixed already in main?

[thorn0]

@sosukesuzuki I only left a comment in babel/babel#13208, but I didn't report this issue properly. There are also issues with let (#10777 (comment)). And there might be more. A good read through the spec is needed.

[sosukesuzuki]

@thorn0 Thank you. I'll investigate specs and report to babel/babel and fix, okay?

[thorn0]

Sounds good 👍 Probably these changes in the spec are recent.

[thorn0]

BTW, here is valid TypeScript that compiles to invalid JS by both the TypeScript compiler and Babel (probably fixed by babel/babel#13208): for ((async as any) of []);