Merge pull request #26512 from TIHan/RaiseChanged-WorkspaceReg

Raise events when connecting or disconnecting from a workspace for semantic changed

src/EditorFeatures/Core/Shared/Tagging/EventSources/TaggerEventSources.SemanticChangedEventSource.cs

@@ -37,11 +37,13 @@ public override void Disconnect()
             protected override void ConnectToWorkspace(Workspace workspace)
             {
                 _notificationService.OpenedDocumentSemanticChanged += OnOpenedDocumentSemanticChanged;
+                this.RaiseChanged();
             }
 
             protected override void DisconnectFromWorkspace(Workspace workspace)
             {
                 _notificationService.OpenedDocumentSemanticChanged -= OnOpenedDocumentSemanticChanged;
+                this.RaiseChanged();
             }
 
             private void OnSubjectBufferChanged(object sender, TextContentChangedEventArgs e)