docs: update standalone installation instruction (#7991)

Co-authored-by: Tim Lai <[email protected]>

Author: ericlingit

docs/usage/installation.md

@@ -165,6 +165,6 @@ The folder `/dist` includes all the HTML, CSS and JS files needed to run Swagger
 
 1. Download the [latest release](https://github.com/swagger-api/swagger-ui/releases/latest).
 1. Copy the contents of the `/dist` folder to your server.
-1. Open `index.html` in your HTML editor and replace "https://petstore.swagger.io/v2/swagger.json" with the URL for your OpenAPI 3.0 spec.
+1. Open `swagger-initializer.js` in your text editor and replace "https://petstore.swagger.io/v2/swagger.json" with the URL for your OpenAPI 3.0 spec.