what does print_config.digits do?

I'm documenting the existing options in the former print_config, and digits
is undocumented, nor have I found any use of it anywhere in the code.
Anyone know why it's there and if there's a reason not to chuck it?

same goes for 'column_space' which is retrieved by GenericArrayFormatter but not used
anywhere in it's methods or those of it's subclasses.

closed via 85b4b11