Add es-x/no-iterator-concat rule

[ota-meshi]

This PR adds a new rule to disallow method from the ES2026 Iterator Sequencing proposal.

https://github.com/tc39/proposal-iterator-sequencing

[changeset-bot]

🦋 Changeset detected

Latest commit: 3905913

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
eslint-plugin-es-x	Minor

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[Copilot]

Pull request overview

This PR adds a new ESLint rule es-x/no-iterator-concat to disallow the Iterator.concat static method from the ES2026 Iterator Sequencing proposal. The implementation follows the established patterns in the codebase for static property rules, using the defineStaticPropertiesHandler helper and including the standard allowTestedProperty option.

• Adds the new rule implementation with proper ES2026 categorization
• Includes test coverage for basic valid and invalid cases
• Integrates the rule into both legacy and flat ESLint configs
• Provides comprehensive documentation with examples and options
• Updates the well-known-properties.js to include concat in alphabetical order
• Includes a minor regex improvement in the docs update script

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
lib/rules/no-iterator-concat.js	New rule implementation using defineStaticPropertiesHandler to detect Iterator.concat usage
tests/lib/rules/no-iterator-concat.js	Basic test coverage for the new rule with valid and invalid cases
lib/index.js	Exports the new rule in alphabetical order
lib/util/well-known-properties.js	Adds concat to the iteratorProperties set in alphabetical order
lib/configs/no-new-in-esnext.js	Enables the rule in the no-new-in-esnext config
lib/configs/flat/no-new-in-esnext.js	Enables the rule in the flat config variant
docs/rules/no-iterator-concat.md	Complete documentation with examples, options, and references
docs/rules/index.md	Adds the rule to the ES2026 rules table
scripts/update-docs-rules.js	Makes description line optional in regex pattern (allows empty descriptions)
.changeset/no-iterator-concat.md	Changeset entry for minor version bump

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