docs(guide/forms): enhanced form examples to utilize $touched
docs(guide/forms): enhanced form examples to utilize $touched

The "Binding to form and control state" example now makes use of
control states that were introduced in 1.3.
For example, users are now informed of validation requirements upon
clicking 'Save'.

Closes #10066

ggershoni/angular.js,ggershoni/angular.js,ggershoni/angular.js,ggershoni/angular.js