Finalize hi-haddock

The hi-haddock work (including a lot of memory optimizations) is now merged into the ghc-9.6 branch the Haddock GitHub repository. This MR ports the work to ghc-head.

.github/workflows/ci.yml

@@ -53,4 +53,4 @@ jobs:
         cabal build all
 
     - name: Test
-      run: cabal test all
+      run: cabal test --test-show-details=direct --test-options="--haddock-stdout=/dev/stdout" all