HTML API: Remove unreachable code from HTML Processor.
The bail() method in WP_HTML_Processor always throws, and it has been documented as returning never since r61699. The return false; sentinels added after its calls in r59001, the break statements following a goto, and the trailing bail() calls at the end of methods whose every path already returns could therefore never run, and PHPStan reported them as unreachable. They are removed. Where a sentinel guarded against a future code path falling off the end of a method, PHPStan now catches that case instead by reporting a missing return.
In step_in_foreign_content(), end tags are now handled in an else branch rather than by re-checking is_tag_closer(), which was always true at that point. This lets both PHPStan and IDEs see that every path returns, so the trailing bail() is no longer needed.
The remaining break statements after a bail() call in a switch are kept. PHPCS cannot tell that bail() never returns, so without a break it treats the case as falling through and misreports the indentation of the comment above the next case. They remain in the baseline, along with two other unreachable statements which mirror steps of the HTML specification.
The outer loop of the adoption agency algorithm is likewise kept, along with its safety budget, as scaffolding for the parts of the algorithm which are not yet supported. Since r64237 PHPStan has reported the loop's two comparisons as constant. Rather than leaving them in baselines that are meant to be emptied, they are now ignored in phpstan.neon.dist with an explanation, and the two baseline files are deleted.
Developed in https://github.com/WordPress/wordpress-develop/pull/14090.
Follow-up to r58836, r59001, r61699, r63023, r64237.
Props westonruter, dmsnell, jonsurrell.
See #65817.
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