fact check for manual: devel bugs

[Graham Percival]

Should bugs in the devel version be sent to lilypond-devel, 
bug-lilypond, or both?

While we're on the subject, could Erik check the section "reporting 
bugs" chapter 4 of the manual (after the next release is ok; it's not 
urgent) ?  I've added some more info, but since you're in charge of 
this stuff, you should check it.  :)

Cheers,
- Graham