T23686: Suggest how to enable Language Extension when in ghci

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See: #23686 (closed)

When using a feature that requires a language extension in a repl it would be nice for ghci to suggest how to enable that extension. Currently, it will show:

ghci> data family GMap k :: * -> *

error:
    • Illegal family declaration for ‘GMap’
        Enable TypeFamilies to allow indexed type families
    • In the data family declaration for ‘GMap’

This will add a suggestion on how to enable the extension in ghci:

      You may enable language extension(s) with:
      :set -XTypeFamilies

If a user needs to enable multiple extensions together then it should look like:

      You may enable language extension(s) with:
      :set -XTypeFamilies -XGADTs -XDataKinds

If a user needs to enable 1 of several extensions then it will have each command on a new line:

      You may enable language extension(s) with:
      :set -XTypeFamilies
      :set -XGADTs
      :set -XDataKinds

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