CQL2-TEXT parsing known issues

Is it possible to build a list of known issues for CQL2-TEXT parsing?
- #68 identifies a problem with `NOT`
- My testing indicates that `T_INTERSECTS` does not work as expected.

#22 is closed as completed, though it's not clear to me if it refers to CQL-TEXT or CQL2-TEXT.

Does anyone know the state of CQL2-TEXT parsing, or do we need to extend [the tests](https://github.com/geopython/pygeofilter/blob/e9b6757372cfa0aa51c6a73098363431b25727c7/tests/parsers/cql2_text/test_parser.py) to understand the current state of the parser? If known issues were documented it would help any project using pygeofilter as it could point to this list when documenting issues with filter support.

Start by reading tests/parsers/cql2_text/test_parser.py and the linked issues #68 and #22 to establish which CQL2-TEXT behaviors are covered. Record the parser's known issues and clarify whether additional tests are needed; done means the current state and limitations are documented for projects using pygeofilter.

Written by the indexing model from the issue text.