Merge pull request #617 from Eelis/trivial

[gram] Re-synchronize generated grammar.tex with grambase.tex.

tools/grambase.tex

@@ -3,8 +3,8 @@
 \begin{paras}
 
 \pnum
-\index{grammar}%
-\index{summary, syntax}%
+\indextext{grammar}%
+\indextext{summary!syntax}%
 This summary of \Cpp\  syntax is intended to be an aid to comprehension.
 It is not an exact statement of the language.
 In particular, the grammar described here accepts
@@ -17,7 +17,7 @@
 \rSec1[gram.key]{Keywords}
 
 \pnum
-\index{keyword}%
+\indextext{keyword}%
 New context-dependent keywords are introduced into a program by
 \tcode{typedef}~(\ref{dcl.typedef}),
 \tcode{namespace}~(\ref{namespace.def}),