ens_name not correctly set in sfcf module

[fjosw]

While going over the type hints in #251 I noticed that ens_name does not seem to get properly propagated in _get_rep_names and _get_appended_rep_names.

https://github.com/fjosw/pyerrors/blame/997d360db37133b7dcbef8b9dbf1e3aff4d7c4bf/pyerrors/input/sfcf.py#L657-L660

Can you have a look @jkuhl-uni ?

[jkuhl-uni]

Oh, you're right, there are a few 's too much. Thanks for noticing, I'll take care of it, this is a quick fix, I guess :)