Manual talk:Parser cache

This is a great start, @DKinzler (WMF)! I've made a few minor edits and typo fixes. I really like that you've integrated the page with Manual:Architectural modules/Cache. For the structure, I wonder if we can borrow from Manual:Object cache. I think a terminology section (canonical, stale) might be helpful and potentially a good place to define invalidation, expiry, and eviction.

I have restructured the page and added a terminology section.