doc: promote YYEOF

* NEWS (Deep overhaul of the symbol and token kinds): New.
* doc/bison.texi: Promote YYEOF over "0" in scanners.
(Token Decl): No longer show YYEOF here, it now works by default.
(Token I18n): More details about YYEOF here.
(Calc++): Just use YYEOF.

NEWS

@@ -74,7 +74,6 @@ GNU Bison NEWS
     %token
         PLUS   "+"
         MINUS  "-"
-        EOF 0  _("end of file")
       <double>
         NUM _("double precision number")
       <symrec*>
@@ -83,7 +82,7 @@ GNU Bison NEWS
 
   In that case the user must define _() and N_(), and yysymbol_name returns
   the translated symbol (i.e., it returns '_("variable")' rather that
-  '"variable"').
+  '"variable"').  In Java, the user must provide an i18n() function.
 
 *** List of expected tokens (yacc.c)
 
@@ -95,6 +94,38 @@ GNU Bison NEWS
   It makes little sense to use this feature without enabling LAC (lookahead
   correction).
 
+*** Deep overhaul of the symbol and token kinds
+
+  To avoid the confusion with typing in programming languages, we now refer
+  to token and symbol "kinds" instead of token and symbol "types".
+
+**** Token kind
+
+  The "token kind" is what is returned by the scanner, e.g., PLUS, NUMBER,
+  LPAREN, etc.  Users are invited to replace their uses of "enum
+  yytokentype" by "yytoken_kind_t".
+
+  This type now also includes tokens that were proviously hidden: YYEOF (end
+  of input), YYUNDEF (undefined token), and YYERRCODE (error token).  They
+  now have string aliases, internationalized if internationalization is
+  enabled.  Therefore, by default, error messages now refer to "end of file"
+  (internationalized) rather than the cryptic "$end".
+
+  In most case, it is now useless to define the end-of-line token as
+  follows:
+
+    %token EOF 0  _("end of file")
+
+  Rather simply use "YYEOF" in your scanner.
+
+**** Symbol kinds
+
+  The "symbol kinds" is what the parser actually uses.  (Unless the
+  api.token.raw %define variable was used, the internal symbol kind of a
+  terminal differs from the corresponding token kind.)
+
+  They are now exposed as a enum, "yysymbol_kind_t".
+
 *** Modernize display of explanatory statements in diagnostics
 
   Since Bison 2.7, output was indented four spaces for explanatory