docs(@angular/cli): correct CSS resource output location in ng build description

The long description stated that resources referenced in CSS, such as images and
fonts, are written and fingerprinted at the root of the output folder. The
application builder writes them to the `media` directory of the browser output,
which is configurable with `outputPath.media`, and only adds a hash when
`outputHashing` is `all` or `media`.

Author: MeAkib

packages/angular/cli/src/commands/build/long-description.md

@@ -13,6 +13,7 @@ Note that in the configuration file, you must specify names in camelCase.
 Some additional options can only be set through the configuration file,
 either by direct editing or with the `ng config` command.
 These include `assets`, `styles`, and `scripts` objects that provide runtime-global resources to include in the project.
-Resources in CSS, such as images and fonts, are automatically written and fingerprinted at the root of the output folder.
+Resources in CSS, such as images and fonts, are automatically written to the `media` directory of the browser output
+(configurable with the `outputPath.media` option) and fingerprinted when `outputHashing` is set to `all` or `media`.
 
 For further details, see [Workspace Configuration](reference/configs/workspace-config).