Postgres Supports a new data-type for JSON data. This datatype is different from text because postgres will guarantee that the data is actually JSON and can perform queries on the data structure.
Thanks for the pull request!
This issue introduced PostgreSQL92Dialect and PostgreSQL94Dialect. These should both be reapplied to the 4.3-based master branch
While you're working on the PostgreSQL dialects, mind taking a quick look at HHH-5654, I think a minor tweak in those dialects could solve that issue as well.