docs($exceptionHandler): add a note about cases when exceptions are not delegated...

...to the $exceptionHandler

Add a note in $exceptionHandler's documentation about cases when exceptions are not delegated to the
$exceptionHandler, because they are executed outside of the Angular context. Most notable such
cases being the DOM event listeners registered using jqLite's/jQuery's on/bind methods.

Closes #7909
$digest is completely unrelated to $exceptionHandler, so it doesn't make sense to bring it up (except maybe to mention that things which happen during digest will pass caught exceptions to $exceptionHandler).

SGTY is "sound good to you"