Fixes#363.
I set out to fix issue #363, but after fixing it discovered some
other things were wrong with the command while testing. In
summary:
- #363 was because it was still assuming a line ending width
of 1 char in its indexing calculations, even when actually
inserting CRLF.
- Aside from #363, it actually needed to set `line_end_index`
to zero for *all* calculations that use it when line == 0,
but it was only doing so for a single calculation.
8935e7a879