Docs: Add reminder about e.stopPropagation() (#247)

Per yoshuawuyts/sheet-router#50

README.md

@@ -555,8 +555,9 @@ html`
 Example listeners include: `onclick`, `onsubmit`, `oninput`, `onkeydown`,
 `onkeyup`. A full list can be found [at the yo-yo
 repo](https://github.com/maxogden/yo-yo/blob/master/update-events.js). When
-creating listeners always remember to call `e.preventDefault()` on the event so
-it doesn't bubble up and do stuff like refreshing the full page or the like.
+creating listeners always remember to call `e.preventDefault()` and
+`e.stopPropagation()` on the event so it doesn't bubble up and do stuff like
+refreshing the full page or the like.
 
 To trigger lifecycle events on any part of a view, set the `onload=${(el) =>
 {}}` and `onunload=${() => {el}}` attributes. These parameters are useful when