EncodingUtils: corrected bound check and step behavior for UTF8Utils::prev().¹
EncodingUtils: corrected bound check and step behavior for UTF8Utils::prev().¹

1: Bound check was backwards. "Lead unit" macro does not include
single units, so prev() wasn't even stepping on them; we can just
explicitly step backwards one step to get out of whatever part we're
in (just like UTF16Utils::prev()).

komiga/duct-cpp