Comment a weird-looking thing.

Author: mkantor

main.ts

@@ -1,5 +1,6 @@
 import { decompressFromBase64 } from "lz-string"
 
+// Expected invocation is `node path/to/index.js $url`.
 if (process.argv.length !== 3) {
   throw new Error(
     "This script expects a single command-line argument (the TypeScript Playground URL to decode).",