Fix some doc errors.

Change-Id: Ib874d7e9671d9cee75fe41f4dac5d0de7b09245e
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>