Show scalafmt configuration errors

[loveleif]

Errors in scalafmt configuration files cause an exception in spotless that does does not contain any information about what went wrong. Scalafmt provides this information and this is a request to bubble it up in spotless.

For example, a scalafmt configuration that contains an invalid field will result in an exception in spotless like this:

java.lang.reflect.InvocationTargetException
   ...
Caused by: java.util.NoSuchElementException: Either.right.value on Left
   at scala.util.Either$RightProjection.get(Either.scala:453
   ...

[nedtwigg]

Released in plugin-maven 2.10.0 and plugin-gradle 5.12.0.