ptx: show no output if input is numeric

[cakebaker]

GNU ptx doesn't show any output if the input is numeric whereas uutils ptx shows some output.

$ printf "123" | ptx
$ echo $?
0
$ printf "1 2 3" | ptx
$ echo $?
0

$ printf "123" | cargo run -q ptx
                                       123
$ printf "1 2 3" | cargo run -q ptx
                                       1 2 3
                                   1   2 3
                                 1 2   3

[oech3]

Also I see gnu9.10/ptx <<< "012345678901234567890123456789🛠" should have empty stdout, but uutils has something.