Add npm install instruction to installation section similar to htmx.org

[htmx.org](https://htmx.org/docs/#npm) does have instruction how to install it via NPM. Hyperscript is also install-able via NPM but this is not documented.

Would it be a good idea to highlight this also in the hyperscript documentation.

Example below from htmx.org replaced with hyperscript (checked the node_modules dir if it exists).

```
npm

For npm-style build systems, you can install hyperscript via [npm](https://www.npmjs.com/):

npm install hyperscript.org

After installing, you’ll need to use appropriate tooling to use node_modules/hyperscript.org/dist/_hyperscript.js (or .min.js). For example, you might bundle hyperscript with some extensions and project-specific code.
```