Use doc-validator v3.0.0 (#69544)

- Structured output for use with [`reviewdog`](https://github.com/reviewdog/reviewdog).
  You can achieve the original error output by piping the output to the following `jq` expression: `jq -r '"ERROR: \(.location.path):\(.location.range.start.line):\(.location.range.start.column): \(.message)"'`.
- Suggestions for simple link fixes.
  In GitHub, [`reviewdog`](https://github.com/reviewdog/reviewdog) comments these suggestions for convenient replacement.
- Support for anchors referring to repeated headings.
  In the case that a page has multiple headings that share the same text, a zero indexed, the renderer appends a numbered suffix to the identifier.
  For example, when there are two headings that are both "Heading text", the first anchor identifier is `heading-text` and the second is `heading-text-1`.- Error when running `doc-validator` on no files.

Signed-off-by: Jack Baldry <jack.baldry@grafana.com>

.github/workflows/doc-validator.yml

@@ -7,7 +7,7 @@ jobs:
   doc-validator:
     runs-on: "ubuntu-latest"
     container:
-      image: "grafana/doc-validator:c2a784f"
+      image: "grafana/doc-validator:v3.0.0"
     steps:
       - name: "Checkout code"
         uses: "actions/checkout@v3"
@@ -20,7 +20,7 @@ jobs:
           ./docs/sources
           /docs/grafana/latest
           | reviewdog
-          '--efm=ERROR: %f:%l:%c %m'
+          -f=rdjsonl
           --fail-on-error
           --filter-mode=nofilter
           --name=doc-validator