how to do a minimalist rebuild of the documentation after minor changes?

[Frédéric Bron]

I have worked a bit with documentation.
I have difficulties to understand:

1. where the documentation goes (where should I find index.html to
browse the doc that was built; I went to out-www but index.html does
not work)
2. how to rebuild the doc when I do some minor changes; for example, I
changed notation/pitches.itely and ??/notation/pitches.itely and I
wanted the doc corresponding to thoses files to be rebuilt.
The only way I found to have it done was "make doc-clean; make doc"
which takes about 3 hours. "make doc" alone does not seem to update
everything properly.

Found nothing about this in the CG.

Any help would be wonderful.

Frédéric