Doc: Regenerate Index button

Remove the workaround from the docs now that we
have the button. Update screenshot.

Change-Id: Ib9e209fa7526749aa0f54e554a6b11e86d53f665
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
C++: Remove initialization of enum variable in DesignatorAST

The tool 'cplusplus-update-frontend' can't handle that and thus will
rewrite that class without this initialization.

The member is properly initialized at use.

Change-Id: I2c8c57be47b5fe953c2518254656e5e38ba90f08
Reviewed-by: Wang Hoi <wanghoi@126.com>
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>