Add exercise_style config and re-enable build cache

- Add exercise_style: solution_follow_exercise for sphinx-exercise
- Re-enable build cache after full execution checks

Author: mmcky

.github/workflows/ci.yml

@@ -44,13 +44,13 @@ jobs:
       - name: Display Pip Versions
         shell: bash -l {0}
         run: pip list
-      # - name: Download "build" folder (cache)
-      #   uses: dawidd6/action-download-artifact@v11
-      #   with:
-      #     workflow: cache.yml
-      #     branch: main
-      #     name: build-cache
-      #     path: _build
+      - name: Download "build" folder (cache)
+        uses: dawidd6/action-download-artifact@v11
+        with:
+          workflow: cache.yml
+          branch: main
+          name: build-cache
+          path: _build
       # Build Assets (Download Notebooks and PDF via LaTeX)
       - name: Build Download Notebooks (sphinx-tojupyter)
         shell: bash -l {0}

lectures/_config.yml

@@ -28,6 +28,8 @@ sphinx:
                        'https://openai.com',
                        'https://chatgpt.com/']
     nb_merge_streams: true
+    # sphinx-exercise
+    exercise_style: "solution_follow_exercise"
     html_favicon: _static/lectures-favicon.ico
     html_theme: quantecon_book_theme
     html_static_path: ['_static']