Improve maintainability of DOCTYPE quirks mode detection in WP_HTML_Doctype_Info class

[baikaresandip]

Trac ticket: https://core.trac.wordpress.org/ticket/65129

Use of AI Tools

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[github-actions]

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[github-actions]

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[mukeshpanchal27]

Thanks for the PR!

The changes look solid to me. As you mentioned, this will run only a single time and should provide a slight performance improvement.