ADD: Viewer - switch to office view mode in the quick view

src/fviewer.pas

@@ -1978,6 +1978,11 @@ begin
           cm_ShowPlugins(['']);
           Key := #0;
         end;
+      '8':
+        begin
+          cm_ShowOffice(['']);
+          Key := #0;
+        end;
     end;
 end;