Finalise 9.4 -- part 2

Includes:

• Update 9.4 release notes regarding withDict (!8632 - closed)
• Fix since annotations in GHC.Stack.CloneStack (!8726 - closed)
• 9.4.1: hadrian: also include boot-generated fil... (!8729 - closed)
• Store interfaces in ModIfaceCache more directly (!8732 - closed)
• Fix haddock_*_perf tests on non-GNU-grep systems (!8282 - closed)
• Store interfaces in ModIfaceCache more directly (!8732 - closed)
• Bump Cabal !8728 (closed)
• Bump Haddock to 7484cf883da0ececa8b9c0e039608d6c20654116 (@Kleidukos)
• Bump containers to 0.6.6 !8709 (closed)
• Bump process. (ticket #21923 (closed))
• Add errror in make build system if ghc is too new !8727 (closed)

TODO:

• Consider Backporting !8277 (merged): Draft !8715.