fix($compile): update '@'-bindings in controller when bindToController is true

'@'-bindings were previously updating the scope when they ought to have been
updating the controller (requested via `bindToController: true` + controllerAs).

It's a one-line fix + test case.

Closes #9052
Closes #9077
docs(ngShowHide): use backticks to denote CSS classes and directive names

add backticks around directive names to improve documentation consistency, as it's used in some
parts of the docs already.

Closes #9081