Log Message:
Update to GHC 8.8.4

The full change log is too long to paste here.

Changes from 8.8.1 to 8.8.2:
https://downloads.haskell.org/~ghc/8.8.2/docs/html/users_guide/8.8.2-notes.html

Changes from 8.8.2 to 8.8.3:
https://downloads.haskell.org/~ghc/8.8.3/docs/html/users_guide/8.8.3-notes.html

Changes from 8.8.3 to 8.8.4:
https://downloads.haskell.org/~ghc/8.8.4/docs/html/users_guide/8.8.4-notes.html