clarified GUI: avoid odd jumping pages on "Cancel";

--- a/src/Tools/jEdit/src/document_dockable.scala	Tue Jan 31 17:35:59 2023 +0100
+++ b/src/Tools/jEdit/src/document_dockable.scala	Tue Jan 31 17:46:16 2023 +0100
@@ -251,7 +251,7 @@
         finish_process(Pretty.separate(msgs))
 
         show_state()
-        show_page(if (Exn.is_interrupt_exn(result)) input_page else output_page)
+        show_page(output_page)
       }
       true
     }