Add sphinx-lint checks to CI (#1327)

* lint

* Ignore ``GenIncProcessModel``

* slashes

.github/workflows/documentation.yml

@@ -74,3 +74,25 @@ jobs:
         --force 
         https://x-access-token:${{ github.token }}@github.com/${{ github.repository }}
         `git subtree split --prefix HARK-docs/html gh-pages`:refs/heads/gh-pages
+
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: Set up Python
+      uses: actions/setup-python@v4
+      with:
+        python-version: 3
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install --upgrade sphinx-lint
+    - name: Lint documentation with sphinx-lint
+      run: >
+        sphinx-lint
+        --ignore Documentation/example_notebooks/GenIncProcessModel.py
+        --enable all
+        --max-line-length 85 
+        README.md
+        Documentation/