Remove jQuery from docs/repo.

Some of the snippets need to be updated later.

.github/CONTRIBUTING.md

@@ -224,7 +224,6 @@ includes code changes) and under the terms of the
 - 2 spaces (no tabs)
 - strict mode
 - "Attractive"
-- Don't use [jQuery event alias convenience methods](https://github.com/jquery/jquery/blob/master/src/event/alias.js) (such as `$().focus()`). Instead, use [`$().trigger(eventType, ...)`](https://api.jquery.com/trigger/) or [`$().on(eventType, ...)`](https://api.jquery.com/on/), depending on whether you're firing an event or listening for an event. (For example, `$().trigger('focus')` or `$().on('focus', function (event) { /* handle focus event */ })`) We do this to be compatible with custom builds of jQuery where the event aliases module has been excluded.
 
 ### Checking coding style