Inconsistent order around disconnectedCallback()

Nobody has claimed this yet.

Between two docs pages I see inconsistent documentation around the order of calls surrounding `super.disconnectedCallback()`.

On the [lifecycle](https://lit.dev/docs/components/lifecycle/#disconnectedcallback) docs. I see the super call come before other code is run:
```
disconnectedCallback() {
super.disconnectedCallback()
window.removeEventListener('keydown', this._handleKeydown);
}
```

On the [events](https://lit.dev/docs/components/events/#adding-event-listeners-to-other-elements) docs. I see the super call come after other code is run:
```
disconnectedCallback() {
window.removeEventListener('resize', this._handleResize);
super.disconnectedCallback();
}
```

Is there a correct order? My assumption given the context is that the _super_ call should be made at the very end of the callback.

Compare the `disconnectedCallback()` examples in the lifecycle and events documentation pages linked in the issue. Determine the correct order for the `super` call, update both examples consistently, and verify that the surrounding guidance matches the chosen order.

Written by the indexing model from the issue text.