docs: fix invalid anchor for CLI flags in deprecation guide (angular#…

…37662)

7521834 added content for CLI
deprecations to the `angular.io` deprecations guide. It looks
like the anchor for the CLI deprecations is incorrect and
ends up showing up as code in the guide.

This commit fixes the anchor so that it doesn't show
up as code in the guide.

PR Close angular#37662

aio/content/guide/deprecations.md

@@ -489,7 +489,7 @@ If you rely on the behavior that the same object instance should cause change de
 - Clone the resulting value so that it has a new identity.
 - Explicitly call [`ChangeDetectorRef.detectChanges()`](api/core/ChangeDetectorRef#detectchanges) to force the update. 
 
-{@ deprecated-cli-flags}
+{@a deprecated-cli-flags}
 ## Deprecated CLI APIs and Options
 
 This section contains a complete list all of the currently deprecated CLI flags.