Fix autofill event downcast - ignore events of the wrong type

[ealmloff]

autofill events don't show up as the right type of event. this pr adds checks for event types and ignores events we don't recognize instead of panicing

It also introduces a unified source for events and event types which deduplicates some code

Fixes #4079
Fixes #5375

[jkelleyrtp]

I will say, glad this fixes the bug, but I don't think the code for the html module really got any cleaner. I think we should look into using proper Rust codegen (build.rs -> html.rs) in a way that's easy to expand for other element systems like TUI / uikit.

[acheul]

Hi! I just found out that ResizeEvent and VisibleEvent are not working on web with this patch.
It seems that they fail "$event_name.is_instance_of::<$web_ty>()" condition (in "web/src/events/mod.rs"). I'd like to contribute a fix, but tbh not very sure where to start.

[ealmloff]

Hi! I just found out that ResizeEvent and VisibleEvent are not working on web with this patch. It seems that they fail "$event_name.is_instance_of::<$web_ty>()" condition (in "web/src/events/mod.rs"). I'd like to contribute a fix, but tbh not very sure where to start.

#5483 should fix this