Fixes#2611 which was a regression from 692216b86a.
The bogus behaviour considered that if there were more than one arguments left to parse,
they would be a pair of arguments (switch and its parameter), and thus skipped the next
argument in all cases (thus potentially skipping a "-editor", which triggered #2611).
This is fixed by checking first for arguments that don't expect a parameter, and only
afterwards for arguments that expect a parameter. And if a "pair" of arguments is not
valid, we no longer increment the counter.
fc2c3bda5c