Try nbsite for the Panel app or parts of it in docs

> [nbsite may be](https://panel.holoviz.org/how_to/wasm/sphinx.html) a better option for the Panel app. [They suggest](https://nbsite.holoviz.org/) pinning nbsite version. Should at least try it.

_Originally posted by @zmoon in https://github.com/zmoon/stringcalc/issues/17#issuecomment-1942031079_
            