feat(pluginpresets) Documentation and log update

docs/user-guides/plugin/plugin-management.md

@@ -21,8 +21,7 @@ In case the _PluginPreset_ is updated all of the Plugin instances that are manag
 Changes that are done directly on a _Plugin_ which was created from a _PluginPreset_ will be overwritten immediately by the _PluginPreset_ Controller. All changes must be performed on the _PluginPreset_ itself.
 If a _Plugin_ already existed with the same name as the _PluginPreset_ would create, this _Plugin_ will be ignored in following reconciliations.
 
-To prevent accidental deletion of the _Plugin_, the _PluginPreset_ has the annotation `greenhouse.sap/prevent-deletion`. To delete the pluginPreset along with the plugins, you must first remove the annotation.
-
+A __PluginPreset__ with the annotation `greenhouse.sap/prevent-deletion` may not be deleted. This is to prevent the accidental deletion of a __PluginPreset__ including the managed __Plugins__ and their deployed Helm releases. Only after removing the annotation it is possible to delete a __PluginPreset__.
 ## Example _PluginPreset_
 
 ```yaml

pkg/admission/pluginpreset_webhook.go

@@ -133,7 +133,7 @@ func ValidateDeletePluginPreset(_ context.Context, _ client.Client, obj runtime.
 	var allErrs field.ErrorList
 	if _, ok := pluginPreset.Annotations[preventDeletionAnnotation]; ok {
 		allErrs = append(allErrs, field.Invalid(field.NewPath("metadata").Child("annotation").Child(preventDeletionAnnotation),
-			pluginPreset.Annotations, "Plugin preset has prevent deletion annotation"))
+			pluginPreset.Annotations, fmt.Sprintf("PluginPreset with annotation '%s' set may not be deleted.", preventDeletionAnnotation)))
 	}
 
 	if len(allErrs) > 0 {