- Don't pollute server logs when types looked for by `TypeInfo.fetch()`
  are not found (:ticket:`#473`).
- Set `Cursor.rowcount` to the number of rows of each result set from
  `~Cursor.executemany()` when called with `!returning=True` (:ticket:`#479`).
- Fix `TypeInfo.fetch()` when used with `ClientCursor` (:ticket:`#484`).