minor fix

* update comments
* NaviLink.uc.js: move function for readability
update text in warning prompt
remove variable referred to only once immediately after
rename onFulfill to clearer onResolve for Promise
use |catch| for Promise
don't async build menuitems after menu is closed
always show sub navi links and page info

* I have not changed its pref to false to disable them.
show alert dialog for command error
test work document URL and content type in each module

* fix no check for them when the export function of module is called
async show menuitems of navi-link