document issue about GDB/MI output syntax

[Joel Brobecker]

> You see there are "nl"s after each line of GDB's message.

Thanks for doing the testing.

I think, at this point, that it's best to just send a doc update
to gdb-patches. Eli is extremely diligent in reviewing code, but
make sure to wait for either Eli or one of the maintainers to
explicitly double-check that the update better matches the code,
and that the code is doing what we wanted it to be (ie, that we're
not turning a bug into law :-)).

Intuitively, I very much doubt there is a bug in the code, but
it's easy to be careful - just need a little bit of quiet time
to think.

-- 
Joel