SVA: add grammar for sequence_match_item

This adds the grammar rules for the first_match operator with sequence match
items.  The operator is still unsupported.

regression/verilog/SVA/sequence_first_match1.sv

@@ -7,4 +7,7 @@ module main(input clk);
 
   initial p0: assert property (first_match(x == 0));
 
+  // can come with sequence_match_items
+  initial p1: assert property (first_match(x == 0, x++));
+
 endmodule

src/verilog/parser.y

@@ -2271,12 +2271,25 @@ sequence_expr:
                 { init($$, ID_sva_sequence_intersect); mto($$, $1); mto($$, $3); }
         | "first_match" '(' sequence_expr ')'
                 { init($$, ID_sva_sequence_first_match); mto($$, $3); }
+        | "first_match" '(' sequence_expr ',' sequence_match_item_brace ')'
+                { init($$, ID_sva_sequence_first_match); mto($$, $3); mto($$, $5); }
         | expression "throughout" sequence_expr
                 { init($$, ID_sva_sequence_throughout); mto($$, $1); mto($$, $3); }
         | expression "within" sequence_expr
                 { init($$, ID_sva_sequence_within); mto($$, $1); mto($$, $3); }
         ;
 
+sequence_match_item_brace:
+	  sequence_match_item
+	| sequence_match_item_brace ',' sequence_match_item
+	;
+
+sequence_match_item:
+	  operator_assignment
+	| inc_or_dec_expression
+	| subroutine_call
+	;
+
 boolean_abbrev:
 	  consecutive_repetition
 	| non_consecutive_repetition