ScalaSeq rule requires blank config or it crashes

[mnd999]

The ScalaSeq rule seems to crash in a confusing way if it's just listed in the rules part of the scalafix configuration without any additional options:

 error: {"rules": ["fix.scala213.ScalaSeq"]} has no field 'fix'.

This is really hard to figure out what is wrong. Adding additional configuration of fix.scala213.ScalaSeq {} makes the rule work, so the configuration is effectively unnecessary.

Can we get a better error here, or at least document this?