React DOM

• Fix mouseenter handlers from firing twice inside nested React containers. @yuanoook in #16928
• Remove unstable_createRoot and unstable_createSyncRoot experimental APIs. (These are available in the Experimental channel as createRoot and createSyncRoot.) (@acdlite in #17088)

Artifacts

• react: https://unpkg.com/react@16.11.0/umd/ • react-art: https://unpkg.com/react-art@16.11.0/umd/ • react-dom: https://unpkg.com/react-dom@16.11.0/umd/ • react-is: https://unpkg.com/react-is@16.11.0/umd/ • react-test-renderer: https://unpkg.com/react-test-renderer@16.11.0/umd/ • scheduler: https://unpkg.com/scheduler@0.17.0/umd/