Defining Multiple Webpack Configurations docs might be missing a step

[iampedropiedade]

I think documentation is missing a step on the assets.yaml to define the multiple manifest.json files:

https://symfony.com/doc/current/frontend/encore/advanced-config.html

framework:
    assets:
        packages:
            app:
                json_manifest_path: '%kernel.project_dir%/public/build/app/manifest.json'
            dashboard:
                json_manifest_path: '%kernel.project_dir%/public/build/dashboard/manifest.json'

instead of the original:

framework:
    assets:
        json_manifest_path: '%kernel.project_dir%/public/build/manifest.json'

#15539

[javiereguiluz]

Fixed in #15539.