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
`try/catch` does only take care of exception handling (no $digest-ing). It would get even more verbose to mention both options (and the consequences of each) and since I mention functions executing outside of the Angular context, I rather wouldn't propose a solution that does not address this (out-of-context issue), but only exception-handling.

That said, if you think it's better to remove all that "Angular context" stuff and just keep it down to exception handling it's fine by me.
Or maybe all the examples should go away.

--
No idea what `SGTY` is though... :)