[MASSMAIL] Postgres_FDW doc doesn't specify TYPE support in Remote Execution Options

I was reading https://www.postgresql.org/docs/current/postgres-fdw.html#POSTGRES-FDW-OPTIONS-REMOTE-EXECUTION and found that it mentions that Immutable Functions and Operators can be pushed down using `extensions` option for foreign server.

But it does not mention about TYPE.

In the shippable.c/lookup_shippable() function, I found that type is also pushed down.