update logical types table for EXPORT INTO PARQUET

Related PR: https://github.com/cockroachdb/cockroach/pull/104234

I missed some details in the release note of the above PR. This [table](https://www.cockroachlabs.com/docs/stable/export.html#parquet-types) needs to be updated to reflect what the new library does.

- For INT/INT8, we use the `INT` logical type. We can also add a note "Note: it signed and has bit width 64"
- For UUID, the logical type should say `UUID`
- We now support the `TUPLE` crdb type which has a `nil` logical type. For the parquet type we can say something similar as to what it says for arrays: "Encoded as a group; each tuple value is encoded as per the preceding types".