* Rename hie-core to ghcide
The name `hie-core` has caused a lot of confusion as to how we relate
to haskell-ide-engine so changing it should hopefully help with that.
I also think that ghcide is still a good name once we hopefully
integrate with haskell-ide-engine more closely.
The name ghcide seems to have a reasonable amount of support on
Twitter https://twitter.com/ndm_haskell/status/1170681262987710464
which is of course the only good way to come up with names.
* Add a readme that points people to the new directory.
* Fix bogus replacements
* Use a proper link
* links are hard