Rewrite runloop guide autorun FAQs

A rewrite of the autorun FAQs in the Runloop guide.

Fixes #1712 #1713 Partially addresses #1390
Again, I think you have a misconception about what is happening.

**Anything that schedules work outside a runloop will schedule an autorun**. Enumerating the various methods is not needed, and distracting to the core concept you are trying to teach.