add: env provide section to environment documentation

docs/en/framework/ui/angular/environment.md

@@ -101,6 +101,22 @@ export interface RemoteEnv {
 - `method`: HTTP method to be used when retrieving environment config. Default: `GET`
 - `headers`: If extra headers are needed for the request, it can be set through this field.
 
+## Provide Environment Variable to Core Module
+
+`environment` variable comes from angular host application.
+
+```js
+import { environment } from '../environments/environment';
+
+@NgModule({
+  imports: [
+    //...other imports
+    CoreModule.forRoot({
+      environment
+    }),
+  ]
+})
+```
 ## EnvironmentService
 
 ` EnvironmentService` is a singleton service, i.e. provided in root level of your application, and keeps the environment in the internal store.