Document use of alignAboveContext and alignBelowContext (issue 6353079)

[PhilEHolmes]

One suggestion, otherwise LGTM.  Thanks.


http://codereview.appspot.com/6353079/diff/1/Documentation/notation/vocal.itely
File Documentation/notation/vocal.itely (right):

http://codereview.appspot.com/6353079/diff/1/Documentation/notation/vocal.itely#newcode1327
Documentation/notation/vocal.itely:1327:
One for Graham really, but it strikes me as wrong to add an example
showing what is effectively incorrect output.  I would have thought it
better to simply say the lyrics go below the bottom staff unless you
tell them explicitly where to go like this...

http://codereview.appspot.com/6353079/