Display more information about why an extension is enabled/disabled

To take one example, we sometimes produce an explanatory message suggesting a user use Type from Data.Kind instead of *, because of -XNoStarIsType. But it would be nice to also explain to the user why -XNoStarIsType is in effect in the first place, as there might be many causes as @rae points out:

• Chosen by a language selection (Haskell98, Haskell2010, or GHC2021). In which case we could recursively say how that language selection was made.
• LANGUAGE pragma in this file.
• Chosen on the command line.
• Set in a cabal file.
• Set in a ghci.conf file.
• Set by :set in a GHCi session.
• Maybe others?

This observation is not limited to -XNoStarIsType, but I don't have other examples to hand at the moment.