WHAT
While completing other tickets in this epic, the documentation should be continously updated. However there are a few places where the upstream docs are out of date which don't fall neatly into the scope of the existing tickets.

This ticket will serve as a catch all for misc. updates to upstream OpenAPI, Product, and Backend docs.

Docs that require updates:

• doc/product-reference.md:
  • The text under the ApplicationPlanSpec section erroneously refers to LimitSpec