yacc: remove support for YYPRINT

Its removal was annonced several times in NEWS (for Bison 3.5, 3.6, 3.7).

* data/skeletons/c.m4, data/skeletons/yacc.c: Remove support for YYPRINT.
* NEWS: Fix the mess introduced by the merge.
Document the removal of YYPRINT.
* doc/bison.texi (The YYPRINT Macro): Remove.

data/skeletons/c.m4

@@ -761,13 +761,6 @@ yy_symbol_value_print (FILE *yyo,
 ]b4_parse_param_use([yyoutput], [yylocationp])dnl
 [  if (!yyvaluep)
     return;]
-dnl glr.c does not feature yytoknum.
-m4_if(b4_skeleton, ["yacc.c"],
-[[# ifdef YYPRINT
-  if (yykind < YYNTOKENS)
-    YYPRINT (yyo, yytoknum[yykind], *yyvaluep);
-# endif
-]])dnl
 b4_percent_code_get([[pre-printer]])dnl
   YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
   b4_symbol_actions([printer])

data/skeletons/yacc.c

@@ -703,15 +703,6 @@ yysymbol_name (yysymbol_kind_t yysymbol)
 }]])[
 #endif
 
-#ifdef YYPRINT
-/* YYTOKNUM[NUM] -- (External) token number corresponding to the
-   (internal) symbol number NUM (which must be that of a token).  */
-static const ]b4_int_type_for([b4_toknum])[ yytoknum[] =
-{
-  ]b4_toknum[
-};
-#endif
-
 #define YYPACT_NINF (]b4_pact_ninf[)
 
 #define yypact_value_is_default(Yyn) \