Feature Request: Make components compatible with MathML

[Jazzpirate]

For a project I'm working on, I wanted to have Popups on MathML nodes. Currently, Popover (and possibly/likely other components?) always use <div> nodes as wrappers for the trigger, which breaks if the trigger occurs in a MathML node. I therefore had to copy-paste your implementation of Popovers and patch it to selectively use <mrow> instead.
Annoyingly, I then realized that I had to also copy the Binder component, since it has a trait guard E::Output: Deref<Target = web_sys::HtmlElement> (and MathML nodes are not HtmlElement). It seems that restriction can be weakened to E::Output: Deref<Target = web_sys::Element> (which MathML nodes implement), since it only seems to be necessary for calls to get_bounding_client_rect, which only requires Element.

My solution was for Popover to take an optional DivOrMrow implemented as

pub enum DivOrMrow {
    #[default]
    Div,
    Mrow,
}

with corresponding enums for NodeRefs, Elements etc.

If you're interested, I could open a pull request

[luoxiaozero]

I changed the child type of PopoverTrigger to be generic in #330. Now you can do:

view! {
    <math display="block">
        <mfrac>
            <Popover>
                <PopoverTrigger slot>
                    <mrow>
                        <mn>"1"</mn>
                        <mo>"+"</mo>
                        <mi>"K"</mi>
                    </mrow>
                </PopoverTrigger>
                "Content 1 + k"
            </Popover>
        </mfrac>
    </math>
}

[Jazzpirate]

Awesome :) One thing that confuses me though is:
in

thaw/thaw/src/popover/mod.rs

Line 44 in f82d8a3

let target_ref = NodeRef::<html::Div>::new();

you still use a NodeRef<Div> and attach that to the child of the trigger - that looks like it should break if that child is not a div-node...?

[luoxiaozero]

It’s so strange, now it can work even if it’s not a div node.

I will improve this.

[Jazzpirate]

Huh, interesting - maybe leptos doesn't actually check that the tag matches when setting the NodeRef signal...? (I assume usually it should match by construction, when used as a node_ref=-attribute, so...)