Update bot to add a comment whenever a xaml file is changed (#6134)

.github/policies/resourceManagement.yml

@@ -1,10 +1,10 @@
-id: 
+id:
 name: GitOps.PullRequestIssueManagement
 description: GitOps.PullRequestIssueManagement primitive
-owner: 
+owner:
 resource: repository
 disabled: false
-where: 
+where:
 configuration:
   resourceManagementConfiguration:
     scheduledSearches:
@@ -155,5 +155,20 @@ configuration:
       - removeLabel:
           label: Status:No recent activity
       description: '[stale community PR] [5-4] Remove "Status:No recent activity" if there are any reviews.'
-onFailure: 
-onSuccess: 
+    - if:
+      - payloadType: Pull_Request
+      - isAction:
+          action: Opened
+      - filesMatchPattern:
+          pattern: '.*\.xaml$'
+          matchAny: true
+      then:
+      - addReply:
+          reply: 'This PR contains changes to XAML files. Verify that you''ve completed the following tasks: 
+        
+        - [ ] Complete [accessibility testing](https://github.com/NuGet/NuGet.Client/blob/dev/docs/ui-guidelines.md#accessibility-testing). 
+        
+        - [ ] Complete [localizability testing](https://github.com/NuGet/NuGet.Client/blob/dev/docs/ui-guidelines.md#localizability-testing).'
+      description: 'Remind PR author to test accessibility and localizability'
+onFailure:
+onSuccess: