Merge symbol_list into master

This merge commit comprises the commits

13da8b2 Rerun scripts/auxiliar/update-with-convert-ly.sh
516cae5 Add more extensive rules for \tweak, \override, \revert, \overrideProperty
7b2cfcb Change \overrideProperty to take a single symbol-list as path
ec6b407 Change \alterBroken interface to match that of other tweak/overrides

that don't have a compilable work tree and should therefore not be
separate commits in the mainline.