feat: support for private-in syntax (fixes #14811)

[ota-meshi]

WIP

Remaining steps:

• wait release acorn.
• release espree.
• update package.json with the new versions of espree. feat: Update espree and eslint-scope #15338

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Fixes #14811.

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request? (put an "X" next to an item)

[ ] Documentation update
[ ] Bug fix (template)
[ ] New rule (template)
[x] Changes an existing rule (template)
[ ] Add autofixing to a rule
[ ] Add a CLI option
[ ] Add something to the core
[x] Other, please explain: Upgrade the espree.

What changes did you make? (Give an overview)

This PR adds support for ES2022 private-in.
I have changed the space-unary-ops rule that we know needs to be changed.

Is there anything you'd like reviewers to focus on?

I checked keyword-spacing rule, which is similar to space-unary-ops rule, but the rule already seems to work well with return#x in obj.

[linux-foundation-easycla]

The committers are authorized under a signed CLA.

• ✅ Yosuke Ota (241f87c)

[eslint-github-bot]

Hi @ota-meshi!, thanks for the Pull Request

The first commit message isn't properly formatted. We ask that you update the message to match this format, as we use it to generate changelogs and automate releases.

• The commit message tag wasn't recognized. Did you mean "docs", "fix", or "feat"?
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[mdjermanovic]

LGTM, thanks! We just need to release espree and update package.json, and then this can be merged.

[btmills]

Espree was just updated in #15338, so this is good to go! LGTM