Keep Types Token Filter

There is a Keep Types Token filter, see

What are the types that you can list in the "types" array?

It uses the Lucene TypeTokenFilter, and it should use the Lucene constants.
I have not used this filter in years, and the types used to be properly
I have not found a better list for Lucene 5/6, or perhaps the Elasticsearch
documentation is using an old constant.

Since it is Lucene, it means it is poorly documented. :slight_smile: Grepping through
the code should find the answers.