docs($compile): clarify linking when there are `templateUrl` directives

Closes #8877
Closes #8631
fix($location): set `baseHref` in mock browser to `/`

Set the default value for the base tag in the mock browser to `/`,
as we now always require a base tag to be present for html5 mode.

Fixes #8866
Closes #8889
docs(errors): fix base href in $location:nobase error page
fix(input): check `scope.$$phase` only on `$rootScope`
fix(ngEventDirs): check `scope.$$phase` only on `$rootScope`

Closes #8891, #8849
style(ngModel): fix spacing
docs(guide/providers): fix grammar and punctuation
docs(changelog): fix inline formatting
docs($rootScope): document scope properties
docs(ngRepeat): update step_02.ngdoc with challenge

Add a simple task for the user to better understand ng-repeat.

Close #8757
style(ngModel): fix indentation
test(orderBy): implement benchmark for ngRepeat with orderBy