In-correct documentation

Continuing the discussion from Alpakka Kafka connector in Akka Streams:

@enru

In case of an error in sources emitted from Consumer.committablePartitionedSource,
the docs says that the subSource is re-emitted and seeked to last committed offset.

However, in the implementation, it looks like we are seeking to the last not emitted offset.

So, in case of any errors, this can cause data loss.