vim instructions change

[Graham Percival]

I'm a bit suspicious about commit
4578dfbfdab5704ffc5317adfb252cb242f30115

1. AFAIK, we definitely want people creating or modifying
~/.vim/filetype.vim
It's just possible that it might be on a different location on
windows, but most people using vim on windows would probably be
using cygwin, so that would still be ~/.vim/ If somebody's doing
something else, they probably know enough to adjust the dir
accordingly.

They *definitely* should not be modifying anything inside
/usr/share/vim/...


2. Unless somebody has manually created a ~/.vim/filetype.vim,
they need to create a new file with the lines which were removed
in the commit.


3. I think the previous runtimepath was wrong, but the new one
isn't much better -- it should point to the locally-installed
version of lilypond, which will not necessarily be at /usr/local/
(for example, I always install it in ~/usr/ )


On a general documentation editing note, don't trust users
blindly.  If somebody makes a suggestion, verify it first -- most
of the time, "verify" just means "run the lilypond example they
gave and see if the output looks good", so this isn't a hard step.
If somebody makes a suggestion about some OS-specific thing or
weird software that you're not familiar with, I'd recommend
caution.  Maybe add a tracker issue asking for somebody (well, a
known+trusted somebody) to check the info, before editing the doc
files.

Cheers,
- Graham