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.
