adding IR links

[Graham Percival]

Could I get 15 minutes of work from somebody familiar with the IR?

Take a look at NR 1.1 Pitches.  Can you find any other
internals reference items for the @seealso list?

If you can, just send me an email listing the extra terms, like:

Accidentals
accidental_note_engraver
sharpSign
whateverTermsTheIRContainsThatSomebodyMightWantToFind

Shape note heads
noteHead

... etc

Cheers,
- Graham