I want to edit HTML of "Url key" field in product editing form in Magento 2 admin area appending some additional HTML to it. Magento 2.2.9.

I tried editing method `UrlKeyRenderer::getElementHtml()` but this method doesn't seem to be called when I open the product editing page, because if I change what the method returns or even if I just throw a `LocalizedException` at the beginning of the method, nothing is changed on the product editing page.

Cleaning page cache with `bin/magento cache:flush` doesn't help.

How do I change the field's HTML?

This is the field I want to edit:

[![enter image description here](https://i.stack.imgur.com/bjcCc.png)](https://i.stack.imgur.com/bjcCc.png)