Add docs-check-links.yml and docs-check-links.sh files in .github/workflows

.github/workflows/docs-check-links.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+set -e
+
+# Check that documentation links work
+
+# The next line returns code 200 only if the page exists
+link_code="$(curl -s -o /dev/null -w "%{http_code}" $URL)"
+
+# Find bad links
+set +e
+good_links="200"
+if [[ "${link_code}" != good_links ]]; then
+    echo "One or more links in the documentation failed:" >&2
+    echo $link_code  >&2
+    exit 1
+fi
+
+exit 0

.github/workflows/docs.yml

@@ -37,6 +37,17 @@ permissions:
   contents: read
 jobs:
 
+  link-checker:
+    if: ${{ always() }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check documentation links
+        run: |
+          .github/workflows/docs-check-links.sh
+        env:
+          # Use GITHUB_TOKEN to avoid rate limiting when checking GitHub links
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
   test-build-docs:
     if: ${{ always() }}
     name: Without ctsm_pylib or container