[MERGE] Add --custom to Version Info in User Guide

[John Arbash Meinel]

John Arbash Meinel has voted tweak.
Status is now: Conditionally approved
Comment:
I just tested it, and it does not handle wrapping using '\'.

Specifically I can type:
bzr.bat version-info --custom \

And when I hit <enter> it starts running the command rather than waiting 
for more input.

So probably a simple comment that says "(on windows this would need to 
be all on one line with no '\'.".
I don't really like how that reads, but something like that.

Ian, could you think of a line and merge this?

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C47C1C760.8080105%40wartburg.edu%3E