- "Double quotes" for strings (filenames, section names, CLI option arguments, etc)
- 'Single quotes' for characters and CLI option flags
- `Backticks` for keywords and identifiers (symbol names, charmap names, etc)
CLI option flags also have their leading dashes
And fix line counting with expansion-made newlines.
This has the same bug as the old lexer (equs-newline's output does not
print the second warning as being part of the expansion).
Additionally, we regress equs-recursion, as we are no longer able to
catch this specific EQUS recursion. Simply enough, the new expansion
begins **after** the old one ends! I have found no way to handle that.
