docs(*): simplify doc urls

we now have two types of namespaces:

- true namespace: angular.* - used for all global apis
- virtual namespace: ng.*, ngMock.*, ... - used for all DI modules

the virual namespaces have services under the second namespace level (e.g. ng.)
and filters and directives prefixed with filter: and directive: respectively
(e.g. ng.filter:orderBy, ng.directive:ngRepeat)

this simplifies urls and makes them a lot shorter while still avoiding name collisions