Also run haddock

Author: hasufell

.github/workflows/test.yaml

@@ -47,6 +47,10 @@ jobs:
       run: cabal build --enable-tests --enable-benchmarks
       shell: bash
 
+    - name: Haddock
+      run: cabal haddock
+      shell: bash
+
     - name: Run tests
       run: cabal test
       shell: bash