add error handler

packages/docs/package.json

@@ -17,18 +17,19 @@
     "esbuild": "^0.14.10",
     "esno": "^0.13.0",
     "express": "^4.17.2",
+    "express-promise-router": "^4.1.1",
     "gray-matter": "^4.0.3",
     "http-terminator": "^3.0.4",
+    "markdown-it": "^12.3.0",
+    "markdown-it-prism": "^2.2.1",
     "pino": "^7.6.2",
     "pino-colada": "^2.2.2",
     "pino-http": "^6.5.0",
+    "postcss": "^8.4.5",
     "reacord": "workspace:*",
     "react": "^18.0.0-rc.0",
     "react-dom": "^18.0.0-rc.0",
-    "postcss": "^8.4.5",
-    "tailwindcss": "^3.0.8",
-    "markdown-it": "^12.3.0",
-    "markdown-it-prism": "^2.2.1"
+    "tailwindcss": "^3.0.8"
   },
   "devDependencies": {
     "@types/browser-sync": "^2.26.3",