tools: bump @node-core/doc-kit

Bumps the doc group with 1 update in the /tools/doc directory: [@node-core/doc-kit](https://github.com/nodejs/doc-kit).


Updates `@node-core/doc-kit` from 1.3.9 to 1.4.0
- [Commits](https://github.com/nodejs/doc-kit/commits)

---
updated-dependencies:
- dependency-name: "@node-core/doc-kit"
  dependency-version: 1.3.10
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: doc
...

Signed-off-by: dependabot[bot] <support@github.com>

tools/doc/package.json

@@ -2,6 +2,6 @@
   "name": "doc",
   "private": true,
   "dependencies": {
-    "@node-core/doc-kit": "1.3.9"
+    "@node-core/doc-kit": "1.4.0"
   }
 }