While it's okay to use ';', the classic Merlin editor will treat it
as an end-of-line comment and shove the entire thing off to the right
side of the screen.
This adds a configuration item to the app settings, with a default
value of ';'.
Generate a 6502 test from the 65816 version by substituting the
16-bit instructions with 8-bit no-ops. There's a lot of project
edits and weird stuff in the test, so this was much easier than
starting over.
The 65816 variant is largely unchanged, though it could now be
stripped down to the stack-offset instructions.
