ini: propose adding vector example to the documentation in help, and the piping website

[iamstein]

For ini, I'd propose adding an example of piping with a parameter vector (instead of just single parameter) to the help documentation and the website. It's easy to do - just use a named vector as input! But I only knew I could do this from talking to Matt.

[mattfidler]

Agreed, and add more new model piping items.

[mattfidler]

Moved to #563