runtime(yaml): do not re-indent when commenting out lines

runtime(yaml): do not re-indent when commenting out lines

It's a personal annoyance for me. I have to edit yaml files on a lot of
customer environments and whenever you type '#' at the start of the
line, the commented line will be indented by whatever indent the
previous line had.

I hate this seriously, because it makes un-commenting painful. So let's
fix this. But instead of messing with the indent function, let's just
remove the '0#' from cinkeys, so that Vim won't perform re-indenting
when commenting out such a yaml file.

closes: #15494

Signed-off-by: Christian Brabandt <cb@256bit.org>