Adding attribute-hover documentation

I'm roughly following the tutorial here: https://blog.jetbrains.com/webstorm/2021/09/building-a-plugin-for-webstorm-part-1/ to create an IntelliJ plugin that adds attributes, along with some documentation.

Whilst the plugin is working great, and I'm getting the auto-complete for my new attributes, the mouse-over documentation for these attributes does not seem to work.

Here's my `web-types` file that I'm using, with the `description` and `doc-url` fields filled in: https://github.com/khalwat/datastar-jetbrains-plugin/blob/develop/src/main/resources/datastar.web-types.json

What am I missing here? Thanks in advance!