Documentation suggestion: transposition resulting in triple accidentals

[Urs Liska]

Hello list,

together with Janek Warchol I ran into trouble transposing harmonically 
complex music.
In order to transpose a piece from e flat to c sharp minor we had to 
first transpose a middle section enharmonically (\transpose e fes) 
because it would otherwise end up having an untolerable amount of double 
sharps.
This gave us a few erroneous results that we had difficulties to track down.

Now I found the reason, and it is that \transpose won't produce triple 
accidentals.
I think this isn't a bug, as triple accidentals don't exist in Lilypond. 
But unfortunately the warnings issued by lilypond don't refer to line 
numbers and are therefore difficult to interpret and didn't lead us to 
the source of the error.

Therefore I'd suggest the following addition to the docs:

---
In NR 1.1.2 (Changing multiple pitches)
At the very end of the section "Transpose"
Please add the following paragraph to "Issues and warnings":

   If \transpose is in a situation where it should produce triple
   accidentals (which it can't) it will use an enharmonically
   equivalent pitch instead (e.g. des instead of eseses). This works on
   individual notes so it will lead to an inconsistent result as only
   some of the notes are affected.

---

Alternatively one could insert a paragraph into the normal section, 
dealing with the use of \transpose to enharmonically change the music 
and putting the note about triple accidentals in this paragraph.
If you think this is more useful, I will write another documentation 
suggestion.

Best
Urs