This continues the work from #2279, by allowing example badges to be specified using `namedParams`. Using an object makes it possible for us to display these in form fields down the line. (#701)
I've called this the "preferred" way, and labeled the other ways deprecated. I've also added some doc to the `examples` property in BaseService. Then I realized we had some doc in the tutorial, though I think it's fine to have a short version in the tutorial, and the gory detail in BaseService.
I've also added a `pattern` keyword, and made `urlPattern` an alias.
Closes#2050.
84a5be3946