doc: don't pretend trigonometry is part of arithmetics

[Akim Demaille]

commit 78e43ce8ff8add0b184d4c0af2968cacf96a8cb8
Author: Akim Demaille <akim.demai...@gmail.com>
Date:   Sat Jan 25 18:35:47 2020 +0100

    doc: don't pretend trigonometry is part of arithmetics
    
    * doc/bison.texi (arith_funs): Rename as...
    (funs): this.

diff --git a/doc/bison.texi b/doc/bison.texi
index b96d2f69..a3b947b0 100644
--- a/doc/bison.texi
+++ b/doc/bison.texi
@@ -2603,7 +2603,7 @@ struct init
 @end group
 
 @group
-struct init const arith_funs[] =
+struct init const funs[] =
 @{
   @{ "atan", atan @},
   @{ "cos",  cos  @},
@@ -2621,16 +2621,16 @@ symrec *sym_table;
 @end group
 
 @group
-/* Put arithmetic functions in table. */
+/* Put functions in table. */
 static void
 init_table (void)
 @end group
 @group
 @{
-  for (int i = 0; arith_funs[i].name; i++)
+  for (int i = 0; funs[i].name; i++)
     @{
-      symrec *ptr = putsym (arith_funs[i].name, FUN);
-      ptr->value.fun = arith_funs[i].fun;
+      symrec *ptr = putsym (funs[i].name, FUN);
+      ptr->value.fun = funs[i].fun;
     @}
 @}
 @end group