The choice regarding which forms should or should not trigger a warning
is subjective. I tried to be consistent and not warn about forms that:
 - run an action, rather than edit data: search, send an email.
 - delete data: a warning about losing data would be confusing

Note that forms on sign-in pages were already ignored (using a selector,
rather than an explicit class on the form element).

Fixes #3698.

* add global code search on explore

* fix bug when no anyone public repos

* change the icon

* fix typo and add UnitTypeCode check for login non-admin user

* fix ui description when no match