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
@caitp, how about those versions:

---
Note, that code executed outside of the Angular context does not delegate exceptions to the `$exceptionHandler` (e.g. functions invoked by third party libraries and callbacks associated with XHR, setTimeout/setInterval and browser DOM events (including callbacks registered using jqLite's/jQuery's `on`/`bind` methods)).
For some of those cases, Angular provides native wrappers that take a care of exception handling (e.g. `$http`, `$timeout`/`$interval`). For the rest, you can explicitly delegate exceptions to the `$exceptionHandler`, e.g.:

    try {
        ...
    } catch (e) {
        $exceptionHandler(e);
    }

---
Note, that code executed inside of event-listeners (even those registered using jqLite's/jQuery's `on`/`bind` methods) does not delegate exceptions to the `$exceptionHandler` (unless executed during a digest).
If you wish, you can manually delegate exceptions (e.g. `try {...} catch(e) {$exceptionHandler(e);}`).