Add support for all native data types

[lovromazgon]

I noticed the library is missing support for some native types, here's a list with the corresponding OID:

• xml (OID: 142)
• macaddr8 (OID: 774)
• money (OID: 790)
• timetz (OID: 1266)
• pg_lsn (OID: 3220)
• tsvector (OID: 3614) (Related: https://github.com/jackc/pgtype/issues/126)
• tsquery (OID: 3615) (Related: https://github.com/jackc/pgtype/issues/126)
• pg_snapshot (OID: 5038)

Would be nice if these would be supported to cover all native types.

[rafiss]

Additionally, I noticed some array types are missing:

• _char (OID: 1002 -- this is the array type for QChar aka "char")
• _name (OID: 1003)
• _timetz (OID: 1270)