next.js

6b9af3e0 - Fix fallback detection logic when multiple generateStaticParams are needed (#47982)

Fix fallback detection logic when multiple generateStaticParams are needed (#47982) ### What? Our current logic of detecting if a route allows dynamic params or not (`fallback`) is flawed, and this PR fixes it. ### Why? Right now, if no `generateStaticParams` is specified we return `fallback: undefined` during dev. However, for an app with multiple params, it may have multiple `generateStaticParams` defined in different levels. If some level isn't covered by any `generateStaticParams`, we still can't determine the fallback value. ### How? I added a naive implementation to check if all params are covered by `generateStaticParams` in the current or inner layers. Closes NEXT-946