message: Add entry documentation
diff: @@ -179,11 +179,12 @@ Your SST app also includes a config file in `sst.json`.
  "stage": "dev",
  "region": "us-east-1",
  "lint": true,
  - "typeCheck": true
  + "typeCheck": true,
  + "main": "infra/index.ts" // Optional => Defaults to "lib/index.(ts/js)
  }
  ```
  -The **stage** and the **region** are defaults for your app and can be overridden using the `--stage` and `--region` options. The **name** is used while prefixing your stack and resource names.
  +The **stage** and the **region** are defaults for your app and can be overridden using the `--stage` and `--region` options. The **name** is used while prefixing your stack and resource names. The **main** is the entry file to your app, defaults to `lib/index.ts` or `lib/index.js` for typescript and Javascript respectively, when you haven't specified the field.
  For JavaScript and TypeScript apps, SST automatically lints your CDK and Lambda function code using [ESLint](https://eslint.org). The **lint** option allows you to turn this off.
  