Applying more of Ben's edits

Author: nastasha-solomon

docs/serverless/investigate/cases-settings.asciidoc

@@ -144,7 +144,7 @@ After creating a new observable type, you can remove or edit it from the **Setti
 
 NOTE: You can create up to 10 custom observable types.
 
-IMPORTANT: If you delete an observable that's using a custom observable type, the observable will no longer exist in the cases to which it was added.
+IMPORTANT: Deleting a custom observable type deletes all instances of it. 
 
 [role="screenshot"]
 image::images/cases-settings/security-cases-observable-types.png[Add an observable type in case settings]