Add CI step to validate documentation changes

Run our documentation generator in "validate only" mode to ensure that
new changes coming in to the repository have documented our changes
fully.

.github/workflows/main.yml

@@ -233,6 +233,17 @@ jobs:
         name: test-results-${{ matrix.platform.id }}
         path: build/results_*.xml
 
+  documentation:
+    name: Validate documentation
+    runs-on: ubuntu-latest
+    steps:
+    - name: Check out repository
+      uses: actions/checkout@v4
+    - name: Validate documentation
+      run: |
+        (cd script/api-docs && npm install)
+        script/api-docs/api-generator.js --validate-only --strict --deprecate-hard  .
+
   test_results:
     name: Test results
     needs: [ build ]