## Description
tsc doesn't understand mixins and ignores jsdoc not followed by code.
The jsdoc for the plugin methods `usingPlugin()` and `hasPlugin()` in
Player are being ignored. To get them included in type outputs we need
to have otherwise unnecessary stubs codes, as we already have for `on()`
etc, which adds unnecessary, even if a small amount of, code to the
outputs.
## Specific Changes proposed
* Slight refactor of Player to include those stubs.
* Adds a rollup plugin to delete lines between certain comments, so
those stubs are deleted from the outputs.
* Applies those comments to the `on()` etc stubs in Component and the
new plugin stubs in Player.
Any code surrounded by these comments, and the comments themselves, is
deleted from the dist and test builds:
```js
/* start-delete-from-build */
console.log('hi');
/* start-delete-from-build */
```
Compared to main, video.min.js is 53 bytes smaller.
## Requirements Checklist
- [ ] Feature implemented / Bug fixed
- [ ] If necessary, more likely in a feature request than a bug fix
- [ ] Change has been verified in an actual browser (Chrome, Firefox,
IE)
- [ ] Unit Tests updated or fixed
- [ ] Docs/guides updated
- [ ] Example created ([starter template on
JSBin](https://codepen.io/gkatsev/pen/GwZegv?editors=1000#0))
- [ ] Has no DOM changes which impact accessiblilty or trigger warnings
(e.g. Chrome issues tab)
- [ ] Has no changes to JSDoc which cause `npm run docs:api` to error
- [ ] Reviewed by Two Core Contributors
