Build(deps-dev): Bump handlebars from 4.7.8 to 4.7.9 in /docs

Bumps [handlebars](https://github.com/handlebars-lang/handlebars.js) from 4.7.8 to 4.7.9.
- [Release notes](https://github.com/handlebars-lang/handlebars.js/releases)
- [Changelog](https://github.com/handlebars-lang/handlebars.js/blob/v4.7.9/release-notes.md)
- [Commits](handlebars-lang/handlebars.js@v4.7.8...v4.7.9)

---
updated-dependencies:
- dependency-name: handlebars
  dependency-version: 4.7.9
  dependency-type: direct:development
...

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

Author: dependabot[bot]

docs/package.json

@@ -12,7 +12,7 @@
   "license": "MIT",
   "devDependencies": {
     "clean-css": "^5.3.3",
-    "handlebars": "4.7.8",
+    "handlebars": "4.7.9",
     "marked": "9.1.6"
   },
   "wireit": {