feat: no-misleading-character-class support v flag

[ota-meshi]

Prerequisites checklist

• I have read the contributing guidelines.

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

[X] Documentation update
[X] Changes an existing rule (template)

What changes did you make? (Give an overview)

Refs #17223

This PR modifies the no-misleading-character-class rule and adds support for regexp v flag.

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

[netlify]

✅ Deploy Preview for docs-eslint canceled.

Name	Link
🔨 Latest commit	90b618e
🔍 Latest deploy log	https://app.netlify.com/sites/docs-eslint/deploys/64bde5fdce3e9a0008cf39b2

[mdjermanovic]

I think this would be a false positive, caused by iterateCharacterSequence yielding 🇯 and 🇵 as consecutive characters although they're not:

/* eslint no-misleading-character-class: "error" */

/[🇯\q{abc}🇵]/v; // error: Unexpected national flag in character class

[ota-meshi]

Thank you for letting me know!
I fixed the iterateCharacterSequence function.

[nzakas]

LGTM. Would like @mdjermanovic to verify being merging.

[mdjermanovic]

This would be a false positive: new RegExp("^[\\q{👶🏻}]$", flags + "v"). However, the problem with unknown flags already exists in this rule, for example new RegExp("[👍]", flags + "u"); was already a false positive before this change, so I think we can evaluate that separately.

[mdjermanovic]

LGTM, thanks!