Add Vale linting to docs pipeline

Also minor fix to doc suite to ensure docs pipeline is triggered.

Also use newest linting image (requires disabling new rule).

.gitlab/ci/docs.gitlab-ci.yml

@@ -44,13 +44,15 @@ docs lint:
     - .default-tags
     - .default-retry
     - .docs:rules:docs-lint
-  image: "registry.gitlab.com/gitlab-org/gitlab-docs:docs-lint"
+  image: "registry.gitlab.com/gitlab-org/gitlab-docs:lint"
   stage: test
   needs: []
   script:
     - scripts/lint-doc.sh
     # Lint Markdown
     - markdownlint --config .markdownlint.json 'doc/**/*.md'
+    # Lint content (error-level text-scoped rules only)
+    - vale --minAlertLevel error --ignore-syntax doc
     # Prepare docs for build
     - mv doc/ /tmp/gitlab-docs/content/$DOCS_GITLAB_REPO_SUFFIX
     - cd /tmp/gitlab-docs

.markdownlint.json

@@ -123,5 +123,6 @@
       "YouTrack"
     ],
     "code_blocks": false
-  }
+  },
+  "code-fence-style": false
 }

doc/administration/geo/disaster_recovery/index.md

@@ -75,7 +75,7 @@ must disable the **primary** node.
    single recommendation. You may need to:
 
    - Reconfigure the load balancers.
-   - Change DNS records (e.g., point the primary DNS record to the **secondary**
+   - Change DNS records (for example, point the primary DNS record to the **secondary**
      node in order to stop usage of the **primary** node).
    - Stop the virtual servers.
    - Block traffic through a firewall.