ESPHome editor needs a "changed" detector/warning

**Describe the problem you have/What new integration you would like**

In virtually every editor I’ve ever used, you are warned when closing the editor if there are any changes to the contents. Not so in the ESPHome editor. You can spend hours editing a configuration only to lose it all if you forget to click on “Save” before exiting.

The editor should set a flag if any text is changed so that when closing the editor, a warning can be displayed.

**Please describe your use case for this integration and alternatives you've tried:**

**Additional context**