Code action to add existing, unused pragma

I have a file with pragmas at the top

```haskell
{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE ExplicitNamespaces #-}
```
DeriveAnyClass is unused, and hlint reports this. But I get a code action to *add* it.

### Your environment
Output of `haskell-language-server --probe-tools` or `haskell-language-server-wrapper --probe-tools`:

```sh
haskell-language-server version: 0.9.0.0 (GHC: 8.8.4) (PATH: /Users/alanzimm/.cabal/store/ghc-8.8.4/hskll-lngg-srvr-0.9.0.0-a8c1156a/bin/haskell-language-server)
Tool versions found on the $PATH
cabal: 3.2.0.0
stack: 2.5.1
ghc: 8.8.4
```
Which lsp-client do you use: emacs lsp-mode

HLS at a065cd66ee129b4f4c2484cfac23f43951587608