docs: update assets configuration to include followSymlinks option (angular#41238)

The `followSymlinks` is not listed in the assets configuration section.

PR Close angular#41238

Author: alan-agius4

aio/content/guide/workspace-config.md

@@ -236,6 +236,7 @@ A asset specification object can have the following fields.
 * `input`: A path relative to the workspace root.
 * `output`: A path relative to `outDir` (default is `dist/`*project-name*). Because of the security implications, the CLI never writes files outside of the project output path.
 * `ignore`: A list of globs to exclude.
+* `followSymlinks`: Allow glob patterns to follow symlink directories. This allows subdirectories of the symlink to be searched. Defaults to `false`.
 
 For example, the default asset paths can be represented in more detail using the following objects.