parser: make println consume parens

examples/hello.v

@@ -1,12 +1,13 @@
-//const (
-//	Cock = 1
-//	Ball = 2
-//	Deals = 3
-//	Businesses = 4
-//)
+const (
+	Cock = 1
+	Ball = 2 + 3
+	Deals = 3
+	Businesses = 4
+)
 
 fn main(a int) int {
 	1 + 2 + 3 + 4
 	1 + 1 * 1
 	3 / (51 + 2)
+	println(2 * 1956)
 }

src/parser.zig

@@ -405,7 +405,11 @@ pub const Parser = struct {
 
     fn parsePrintln(self: *@This()) !*Stmt {
         _ = try self.consumeSingle(.Println);
+
+        _ = try self.consumeSingle(.LeftParen);
         var expr = try self.parseExpr();
+        _ = try self.consumeSingle(.RightParen);
+
         return try Stmt.mkPrintln(self.allocator, expr.Expr);
     }