[DOCS] Remove obsolete section (#4077)

docs/en/observability/manage-cases.asciidoc

@@ -152,16 +152,4 @@ To view a case, click on its name. You can then:
 * Remove an alert.
 * Refresh the case to retrieve the latest updates.
 * Close the case.
-* Reopen a closed case.
-
-[discrete]
-[[observability-case-templates]]
-== Case templates
-
-preview::[]
-
-You can make the case creation process faster and more consistent by adding templates in *Cases -> Settings*.
-A template defines values for one or all of the case fields (such as severity, tags, description, and title) as well as any <<case-custom-fields,custom fields>>.
-When users create cases, they can optionally select a template and use its field values.
-
-NOTE: If you update or delete templates, existing cases are unaffected.
+* Reopen a closed case.