* doc/misc/calc.texi (Musical Notes): Fix build with Texinfo 4.13.

diff --git a/doc/misc/calc.texi b/doc/misc/calc.texi
index 00c0fa6001a0d43adad3f0ad287d54cf70bce883..5064f76e7b829fadd49ece810913c16f0dee762f 100644 (file)
--- a/doc/misc/calc.texi
+++ b/doc/misc/calc.texi
@@ -28476,12 +28476,12 @@ B and
 the octave numbered 0 was chosen to correspond to the lowest
 audible frequency.  Using this system, middle C (about 261.625 Hz)
 corresponds to the note @slanted{C} in octave 4 and is denoted
-@slanted{C@sub{4}}.  Any frequency can be described by giving a note plus an
+@slanted{C4}.  Any frequency can be described by giving a note plus an
 offset in cents (where a cent is a ratio of frequencies so that a
 semitone consists of 100 cents).
 
 The midi note number system assigns numbers to notes so that
-@slanted{C@sub{-1}} corresponds to the midi note number 0 and @slanted{G@sub{9}}
+@slanted{C-1} corresponds to the midi note number 0 and @slanted{G9}
 corresponds to the midi note number 127.   A midi controller can have
 up to 128 keys and each midi note number from  0 to 127 corresponds to
 a possible key.