[diff.mods.to.definitions] Remove superfluous indexing

Author: jensmaurer

source/compatibility.tex

@@ -3641,15 +3641,13 @@
 by \libheaderref{iso646.h}.
 
 \rSec3[diff.header.stdalign.h]{Header \tcode{<stdalign.h>}}
-\indexhdr{stdalign.h}%
 
 \pnum
 The token \keyword{alignas} is a keyword in \Cpp{}\iref{lex.key},
 and is not introduced as a macro
 by \libheaderref{stdalign.h}.
 
 \rSec3[diff.header.stdbool.h]{Header \tcode{<stdbool.h>}}
-\indexhdr{stdbool.h}%
 
 \pnum
 The tokens \keyword{bool}, \keyword{true}, and \keyword{false}