10.10.4 Automatically update documentation

convert-ly should be used to update the documentation, the snippets, and the regression tests. This not only makes the necessary syntax changes, it also tests the convert-ly rules.

The automatic updating is performed by moving to the top-level source directory, then running:

scripts/auxiliar/update-with-convert-ly.sh

If you did an out-of-tree build, pass in the relative path:

LILYPOND_BUILD_DIR=../build-lilypond/ scripts/auxiliar/update-with-convert-ly.sh