Doc: Issue 3324: Add explanation of clashing note columns warning (issue 154640043 by address@hidden)

[k-ohara5a5a]

LGTM

Just for your interest, I have been thinking that when the user gives
explicit \voiceOne or \shiftOn to the voices, Lily should set those
voices at the shifts requested, even if two voices have the same shift
<https://codereview.appspot.com/132110043/>
Currently users are required to set 'ignore-note-collision in these
cases, but then that turns off all the other chord-collision code.


https://codereview.appspot.com/154640043/diff/1/Documentation/usage/running.itely
File Documentation/usage/running.itely (right):

https://codereview.appspot.com/154640043/diff/1/Documentation/usage/running.itely#newcode1112
Documentation/usage/running.itely:1112: (@code{\stemDown}, etc) or
implicitly (@code{\voiceOne}, etc.)
People tend to use \stemDown when they want \voiceTwo, so maybe skip
mention of \stemDown.

I wish there were no shorthand for changing just the stem direction
without the other changes required for consistency.

https://codereview.appspot.com/154640043/