Misc doc updates

Starting to do a complete review of all the Relish docs. I often find myself using these daily or trying to point users to them. I've created a list of things that need updating / adding. This is the first pass on the core docs fixing mostly minor issues.

There are a few consistency issues I'd like to get some guidance one / set a standard:

- [ ] Capitalize the first word of scenarios; these read more like sentences and section titles, which should be capitalized
- [ ] Use back ticks for inline code consistently

**DO NOT MERGE YET**