Consolidate and clarify templating documentation

[dandv]

Thanks for the previous work on this.

Two more points:

1. Templates are often referred to as "extended templates". This may create the impression that there's a regular (or built-in) kind of templates as well. Should we clarify this terminology? What do "extended" templates actually mean? That the templating system is designed to run arbitrary templating languages (with Mustache being the only one currently implemented)? Can we drop "extended" or do we need to keep it to parallel "extended components", which do have a built-in counterpart?

2. The templates spec is actually less detailed than the templates section in the HTML format spec. I was improving the templates documentation when I realized this.

[ericlindley-g]

@dandv, marking as "Current", on the assumption that you're working on this now, but please correct me if I'm wrong!

[ericlindley-g]

cc/ @bpaduch

[dandv]

@ericlindley-g, sorry, wasn't working on this and won't have cycles this week :(

[ericlindley-g]

No worries—I flagged it more as a way to convey information than to push a deadline. I'll just put to "backlog" for now

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions.