Fix a few documentation issues: - Drop unneeded \fn - Sort \brief and \tparam correctly - Add missing \tparam and \param - Explain the T and U template parameters for get() - Standardize the naming of dictionary keys as "key" - Fix typo Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com> Reviewed-by: Isaac Scott <isaac.scott@ideasonboard.com>