Confusing error message if you forget the width of the * format specifier

[alercah]

Playground link: https://play.rust-lang.org/?gist=fea3e7d4c4151751bb66b69ba906ea88&version=stable

If the * formatting specifier is used, it expects an additional argument. But it does not account for this when printing an error message, so in the above example where an argument was forgotten, the error is "error: 1 positional argument in format string, but there is 1 argument". It should indicate that there are in fact 2 positional arguments in the format string, due to *.