print col.names="none" suppresses print completely

It happens that col.names="none" suppresses printing of data.table completely, using default "auto" prints data.table, but goal is to print it without headers. ```r d = data.table(c1 = 1:2, c2 = letters[1:2]) print(d, nrows = Inf, class = FALSE, row.names = FALSE, show.indices = FALSE, print_keys = FALSE, col.names = "none") ## should print! print(d, nrows = Inf, class = FALSE, row.names = FALSE, show.indices = FALSE, print_keys = FALSE, col.names = "auto") # c1 c2 # 1 a # 2 b packageVersion("data.table") #[1] ‘1.18.99’ ```