looks great! very rudimental at this point, would be fine for inclusion as is and we can add new things to it as needed. next step would be a little bit of test coverage in test/dialect/postgresql/test_types.py
I've included tsvector in the list of types tested and found that reflection didn't work. I've fixed that. There are no tests for the expression level routines yet though. Do you think it's good enough to put in or should I work on those first?