text: Title: remove any types from core public plugin API
  Body: Core team currently has the most `any` types in the public API. Let's get that down!
  
  <img width="1028" alt="Screen Shot 2021-05-06 at 2 14 29 PM" src="https://user-images.githubusercontent.com/16563603/117346871-5461c680-ae76-11eb-92ee-8d98178511ff.png">
  
  Run 
  
  `node scripts/build_api_docs --stats any --plugin core` 
  
  for a full list with links of every item:
  
  <img width="1378" alt="Screen Shot 2021-05-06 at 2 37 36 PM" src="https://user-images.githubusercontent.com/16563603/117348783-9ee44280-ae78-11eb-9291-09aa485fa882.png">
  
  
  
  
  