[ fix ] Add dummy handler for SCancelRequest notifications (hope that this is the last one we need)

Author: banacorn

src/Server.hs

@@ -112,7 +112,8 @@ handlers =
       notificationHandler SInitialized $ \_not -> pure (),
       notificationHandler STextDocumentDidOpen $ \_not -> pure (),
       notificationHandler STextDocumentDidSave $ \_not -> pure (),
-      notificationHandler STextDocumentDidChange $ \_not -> pure ()
+      notificationHandler STextDocumentDidChange $ \_not -> pure (),
+      notificationHandler SCancelRequest $ \_not -> pure ()
       -- -- syntax highlighting
       -- , requestHandler STextD_cumentSemanticTokensFull $ \req responder -> do
       --   result <- Handler.onHighlight (req ^. (params . textDocument . uri))