Add a recipe for ghc-imported-from

This package provides an Emacs command for running and processing the
output of ghc-imported-from, which is a command-line app for determining
the Haddock documentation page for a symbol in a Haskell program.

The package repository is at
https://github.com/david-christiansen/ghc-imported-from-el

I am the author and maintainer of the package.
Merge pull request #2182 from david-christiansen/ghc-imported-from

Add a recipe for ghc-imported-from