community/lilypond: upgrade to 2.25.16
--disable-texi2html
is removed in https://gitlab.com/lilypond/lilypond/-/merge_requests/2111.
The autogen.sh in prepare was previously not needed since we were downloading the tarball that packed the configure script. Since v2.25.16 is a development release, it is only available on gitlab, where the configure script is not bundled with the released tarball (https://lilypond.org/doc/v2.25/Documentation/contributor/running-autogen_002esh).
Edited by Coco Liliace