add cli option that lets you include escape codes as useless attributes

[masukomi]

let's say we convert <ESC>[38m to <span style="color: red; "> for educational and debugging purposes it would be useful to know what color code created the span. This is especially true with the more obscure / exotic color codes and compound ones like [38;2;252;0;37m

suggested output would be <span style="color: red; " escape_code="[38m">

this would NOT be on by default. As far as i know no escape codes use " or ' so we shouldn't have to worry about the contents of the attribute screwing up the quoting.