docs(guide/Directives): improve description of linking function
docs(guide/Directives): improve description of linking function

The `controller` and `transclude` parameters of the linking function were not
mentioned in the description, but used in the examples.
This commit improves the description and links to the `$compile` API docs
for more details.

Closes #13028

Smartbank/angular.js,Smartbank/angular.js,Smartbank/angular.js,Smartbank/angular.js