Fix lit-plugin auto-import for components with Lumo theme

[web-padawan]

Currently, when using vscode-lit-plugin, the auto import feature does not work as expected:

https://user-images.githubusercontent.com/10589913/102873974-7ff58e80-444a-11eb-848e-1dda8d546476.mov

The imported file is the one which contains HTMLElementTagNameMap interface definition: the one under src. However, the unstyled components aren't meant to be imported as we want our users to import Lumo entrypoints.

Let's consider changing this so that the root entrypoints would register the class under HTMLElementTagNameMap

Not sure if we can make it work for Material as well. For now we can only do it for Lumo.

[jcgueriaud1]

Do you have any changes planned for Vaadin 20?

[web-padawan]

This is not something we planned to ship in Vaadin 20. Let's consider it as a possible improvement before next LTS though.

[manolo]

Any progress or ETA for this ?

[web-padawan]

This is not something we can deliver in a patch release. But probably it can be done in a minor, e.g. Vaadin 23.2

[manolo]

It will be nice if we have that sooner, it's quite upsetting having to manually edit each single import after the IDE adds it, specially when demoing hilla in conferences