Add a FAQ?

### Background

While adding #374 , I had the thought that maybe a FAQ for our examples might be worth having.

### Problem

We have some _opinions_ about coding style, etc. that might be somewhat unfamiliar to people. In training, we often get questions about things like:
* "Why do you use `::` so much?"
* "Why do you use `read_tsv()` instead of `read.delim()`?"
* "What if I want to use python?"

Maybe laying some of these out explicitly would be something we could do.
As we test the example pages, more things might come up that might be best addressed by a short FAQ entry than by any major modifications. This would be a nice place to centralize some of these questions.

Review the example pages and the questions listed in this issue, including the use of `::`, `read_tsv()`, `read.delim()`, and Python. The issue does not name a file or entry point, so first determine where example documentation lives. Done means the recurring questions and project opinions are centralized in a documented FAQ.

Written by the indexing model from the issue text.