Apply suggestions to fix typescript compilation

Co-authored-by: Jason Grout <[email protected]>

Author: consideRatio

src/widget.ts

@@ -29,8 +29,7 @@ class SidecarModel extends OutputModel {
 
   initialize(attributes: any, options: any) {
     super.initialize(attributes, options);
-    // FIXME: Argument of type 'undefined' is not assignable to parameter of type 'IMessage<MessageType>'.
-    this.widget_manager.display_model(undefined, this, {});
+    this.widget_manager.display_model(undefined as any, this, {});
   }
 
   static serializers : any = {

tests/src/utils.spec.ts

@@ -21,8 +21,7 @@ class MockComm {
     on_msg(fn: Function | null) {
         this._on_msg = fn;
     }
-    // FIXME: Namespace '"REDACTED/jupyterlab-sidecar/node_modules/@jupyterlab/services/lib/kernel/messages"' has no exported member 'ICommMsg'.
-    _process_msg(msg: services.KernelMessage.ICommMsg) {
+    _process_msg(msg: services.KernelMessage.ICommMsgMsg) {
         if (this._on_msg) {
             return this._on_msg(msg);
         } else {