All encodings documented in Texinfo manual are spelled uppercase.
This will hopefully fix problems with accents in Spanish manual.
@end ignore
@setfilename lilypond.info
@settitle Manual del usuario de GNU LilyPond
-@documentencoding utf-8
+@documentencoding UTF-8
@documentlanguage es
@iftex
@end ignore
@setfilename lilypond-program.info
@settitle GNU LilyPond program usage
-@documentencoding utf-8
+@documentencoding UTF-8
@documentlanguage en
@iftex
@end ignore
@setfilename lilypond.info
@settitle GNU LilyPond user manual
-@documentencoding utf-8
+@documentencoding UTF-8
@documentlanguage en
@iftex