Allow gcode comments in (parenthesis) since some controllers error on semicolon comments

[easytarget]

Following a thread on Makerforums, this looks like an feature request we should, at least, capture. https://forum.makerforums.info/t/changeable-standard-sign-for-comments-in-gcode/86432/

I'm thinking about a comments replacement string setting, something like ; $comment which can be changed to `( $comment ) etc at will.