build(deps): bump @mdit/plugin-footnote from 0.12.0 to 0.22.1

Bumps [@mdit/plugin-footnote](https://github.com/mdit-plugins/mdit-plugins/tree/HEAD/packages/footnote) from 0.12.0 to 0.22.1.
- [Release notes](https://github.com/mdit-plugins/mdit-plugins/releases)
- [Changelog](https://github.com/mdit-plugins/mdit-plugins/blob/main/packages/footnote/CHANGELOG.md)
- [Commits](https://github.com/mdit-plugins/mdit-plugins/commits/@mdit/[email protected]/packages/footnote)

---
updated-dependencies:
- dependency-name: "@mdit/plugin-footnote"
  dependency-version: 0.22.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package.json

@@ -6,7 +6,7 @@
     "format": "prettier --write ."
   },
   "dependencies": {
-    "@mdit/plugin-footnote": "^0.12.0",
+    "@mdit/plugin-footnote": "^0.22.1",
     "@mdit/plugin-img-mark": "^0.13.1",
     "aplos": "2.5.0",
     "prettier": "^3.3.3"