Add build step to start docs

Author: sylhare

package.json

@@ -19,6 +19,7 @@
     "test:benchmark": "NODE_OPTIONS='--max-old-space-size=4096' vitest run tests/performance/",
     "test:watch": "vitest",
     "start": "cd docs; jekyll serve",
+    "prestart:docs": "yarn run build",
     "start:docs": "cd docs && bundle exec jekyll serve"
   },
   "repository": {