chore: bump GHC to 9.8.2

Also Weeder to 2.8.0.

Also, `haskell.nix` does not yet support HLS 2.7, but we can work
around it.

Signed-off-by: Drew Hess <src@drewhess.com>

flake.nix

@@ -4,6 +4,9 @@
   inputs = {
     haskell-nix.url = "github:input-output-hk/haskell.nix";
 
+    # Until `haskell.nix` catches up.
+    "hls-2.7" = { url = "github:haskell/haskell-language-server/2.7.0.0"; flake = false; };
+
     # We use this for some convenience functions only.
     hacknix.url = "github:hackworthltd/hacknix";
 
@@ -44,11 +47,11 @@
         in
         builtins.trace "Nix Primer version is ${v}" "git-${v}";
 
-      ghcVersion = "ghc981";
+      ghcVersion = "ghc982";
 
       # We must keep the weeder version in sync with the version of
       # GHC we're using.
-      weederVersion = "2.6.0";
+      weederVersion = "2.8.0";
 
       # Fourmolu updates often alter formatting arbitrarily, and we want to
       # have more control over this.
@@ -492,7 +495,7 @@
 
                     # Workaround for HLS in haskell.nix. Ref:
                     # https://github.com/input-output-hk/haskell.nix/issues/1981#issuecomment-1594278049
-                    haskell-language-server.src = pkgs.haskell-nix.sources."hls-2.6";
+                    haskell-language-server.src = inputs."hls-2.7";
 
                     implicit-hie = "latest";