packages/cli: fix and document watch mode

packages/cli/package.json

@@ -18,13 +18,12 @@
   "license": "Apache-2.0",
   "main": "dist",
   "scripts": {
-    "exec": "npx ts-node ./src",
     "build": "backstage-cli build-cache -- tsc",
     "lint": "backstage-cli lint",
     "test": "backstage-cli test",
     "test:e2e": "node e2e-test/cli-e2e-test.js",
     "clean": "backstage-cli clean",
-    "start": "nodemon ."
+    "start": "nodemon --"
   },
   "devDependencies": {
     "@types/fs-extra": "^8.1.0",
@@ -92,7 +91,7 @@
   ],
   "nodemonConfig": {
     "watch": "./src",
-    "exec": "ts-node ./src",
+    "exec": "bin/backstage-cli",
     "ext": "ts"
   }
 }