Mention not using resize event in contributing docs

Author: interactivellama

CONTRIBUTING.md

@@ -35,6 +35,7 @@ We'll review your code, suggest any needed changes, and merge it in. Thank you.
 - <a name="event-callbacks" href="#event-callbacks">#</a> Event callbacks should pass in the synthetic event, then a data object with contents that relate to the event.
 - <a name="boolean-prop-prefix" href="#boolean-prop-prefix">#</a> If a prop is a boolean, please prefix with `is` or `can` or suffix it with `-able`. Never default a prop to `true`.
 - <a name="use-checkprops" href="#use-checkprops">#</a> Add as many prop checking tests that will _only run in development_ as needed via `checkProp`. If the test can become an independent module and work in multiple components, add it to the `utilities` folder.
+- <a name="no-window-events" href="#no-window-events">#</a> Global window events like `resize` or external DOM nodes should not be accessed from the component. If needed, `body` can be used for additional mount nodes. If a menu needs to be smaller to be responsive, consuming applications should listen for the resize event and change the correct props to make the component responsive--or a CSS solution should be found. The component should not be listening to the event directly. Global key press or mouse clicks are fine if used appropriately.
 - <a name="all-text-can-be-internationalized" href="#all-text-can-be-internationalized">#</a> Any text the user can read (including text for screenreaders) should be able to be set via a prop for internationalization.
 - <a name="avoid-css" href="#avoid-css">#</a> Avoid use of inline styles and additional CSS classes not present in SLDS.
 - <a name="different-react-component-hierarchy" href="#different-react-component-hierarchy">#</a> React component hierarchy doesn't always mean HTML tag hierarchy. Sometimes children become the wrapping component.