bug in 2nd-highest-upvoted mb_check_encoding() comment code

the comment
https://www.php.net/manual/en/function.mb-check-encoding.php#95289 is the
2nd-highest upvoted comment, and makes some dubious claims, but the code
provided is bugged and should not be used,
as a specific example it incorrectly validates "\xC0\x81"  , which is
illegal  in UTF8 (quote RFC3629: The octet values C0, C1, F5 to FF never
appear - ref https://datatracker.ietf.org/doc/html/rfc3629 )

so.. can we at least get an editor's note that the code is bugged,
incorrectly validates "\xC0\x81", and should not be used?