docs(configuration): clarify the location of app.config.ts in the s…

…ource directory (#9937)

docs/content/1.docs/1.getting-started/3.configuration.md

@@ -69,7 +69,7 @@ const runtimeConfig = useRuntimeConfig()
 
 ## App Configuration
 
-The `app.config.ts` file, also located at the root of a Nuxt project, is used to expose public variables that can be determined at build time. Contrary to the `runtimeConfig` option, these can not be overridden using environment variables.
+The `app.config.ts` file, located in the source directory (by default the root of the project), is used to expose public variables that can be determined at build time. Contrary to the `runtimeConfig` option, these can not be overridden using environment variables.
 
 A minimal configuration file exports the `defineAppConfig` function containing an object with your configuration. The `defineAppConfig` helper is globally available without import.
 
@@ -112,8 +112,6 @@ Configuration per Request      | ❌ No            | ✅ Yes
 Hot Module Replacement         | ❌ No            | ✅ Yes
 Non primitive JS types         | ❌ No            | ✅ Yes
 
-:ReadMore{link="/docs/guide/directory-structure/external-configuration"}
-
 ## External Configuration Files
 
 Nuxt uses `nuxt.config.ts` file as the single source of trust for configurations and skips reading external configuration files. During the course of building your project, you may have a need to configure those. The following table highlights common configurations and, where applicable, how they can be configured with Nuxt.