feat: namespaced attributes

this commit adds namespaced attributes. This lets us support attribute groups, and thus, inline styles.

This namespaced attribute stuff is only available for styles at the moment, though it theoretically could be enabled for any other attributes.

examples/readme.rs

@@ -2,7 +2,9 @@
 //!
 //! The example from the README.md
 
-use dioxus::prelude::*;
+use dioxus::{events::on::MouseEvent, prelude::*};
+use dioxus_html_namespace::{button, div, h1};
+
 fn main() {
     dioxus::web::launch(Example)
 }
@@ -10,9 +12,11 @@ fn main() {
 fn Example(cx: Context<()>) -> VNode {
     let name = use_state(&cx, || "..?");
 
+    let handler = move |e: MouseEvent| e.cl;
+
     cx.render(rsx! {
         h1 { "Hello, {name}" }
-        button { "?", onclick: move |_| name.set("world!")}
+        button { "?", onclick: move |event| name.set("world!")}
         button { "?", onclick: move |_| name.set("Dioxus 🎉")}
     })
 }