Missing JSDOC

Out of the box the files included in this template trigger `ESLint` error, see:

```js
REDACTED\src\serviceWorkerRegistration.js
   23:8  error  Missing JSDoc comment  require-jsdoc
   63:1  error  Missing JSDoc comment  require-jsdoc
  110:1  error  Missing JSDoc comment  require-jsdoc
  141:8  error  Missing JSDoc comment  require-jsdoc
```