style: s/non-terminal/nonterminal/

I personally prefer 'non terminal', or 'non-terminal', but
'nonterminal' is the common spelling.

* data/glr.c, src/parse-gram.y, src/symtab.c, src/symtab.h,
* tests/input.at, doc/refcard.tex: here.

src/parse-gram.c

@@ -2705,7 +2705,7 @@ yyreduce:
       if (current_class == nterm_sym)
         {
           gram_error (&(yylsp[0]),
-                      _("character literals cannot be non-terminals"));
+                      _("character literals cannot be nonterminals"));
           YYERROR;
         }
       (yyval.id) = symbol_get (char_name ((yyvsp[0].CHAR)), (yylsp[0]));

src/parse-gram.y

@@ -641,7 +641,7 @@ id:
       if (current_class == nterm_sym)
         {
           gram_error (&@1,
-                      _("character literals cannot be non-terminals"));
+                      _("character literals cannot be nonterminals"));
           YYERROR;
         }
       $$ = symbol_get (char_name ($1), @1);

src/state.h

@@ -117,7 +117,7 @@ typedef struct
 
 /* What is the symbol labelling the transition to
    TRANSITIONS->states[Num]?  Can be a token (amongst which the error
-   token), or non terminals in case of gotos.  */
+   token), or nonterminals in case of gotos.  */
 
 # define TRANSITION_SYMBOL(Transitions, Num) \
   (Transitions->states[Num]->accessing_symbol)

src/symtab.c

@@ -478,7 +478,7 @@ symbol_user_token_number_set (symbol *sym, int user_token_number, location loc)
   int *user_token_numberp = &sym->content->user_token_number;
   if (sym->content->class != token_sym)
     complain (&loc, complaint,
-              _("non-terminals cannot be given an explicit number"));
+              _("nonterminals cannot be given an explicit number"));
   else if (*user_token_numberp != USER_NUMBER_UNDEFINED
            && *user_token_numberp != user_token_number)
     complain (&loc, complaint, _("redefining user token number of %s"),
@@ -614,7 +614,7 @@ symbol_make_alias (symbol *sym, symbol *str, location loc)
 {
   if (sym->content->class != token_sym)
     complain (&loc, complaint,
-              _("non-terminals cannot be given a string alias"));
+              _("nonterminals cannot be given a string alias"));
   else if (str->alias)
     complain (&loc, Wother,
               _("symbol %s used more than once as a literal string"), str->tag);
@@ -677,7 +677,7 @@ complain_user_token_number_redeclared (int num, symbol *first, symbol *second)
 static inline bool
 symbol_translation (symbol *this)
 {
-  /* Non-terminal? */
+  /* Nonterminal? */
   if (this->content->class == token_sym
       && !this->is_alias)
     {

src/symtab.h

@@ -40,7 +40,7 @@ typedef enum
 {
   unknown_sym,          /**< Undefined.  */
   token_sym,            /**< Terminal. */
-  nterm_sym             /**< Non-terminal. */
+  nterm_sym             /**< Nonterminal. */
 } symbol_class;