Adds ability to use multiple classes in view macro using array syntax.

[bicarlsen]

Adds array syntax to the fancy class name syntax in the view macro for multiple classes to be controlled by the same class attribute.
e.g.

#[component]
fn App() -> impl IntoView {
  let (classes, set_classes) = create_signal(true);

  view! {
    <div
      class=(["class-1", "class-2"], classes)
    >
      <button
        on:click=move |_| set_classes(!classes)
      >
        Toggle
      </button>
    </div>
  }
}

Compared to the current style which requires creating a new class attribute for each class.
e.g.

#[component]
fn App() -> impl IntoView {
  let (classes, set_classes) = create_signal(true);

  view! {
    <div
      class=("class-1", classes)
      class=("class-2", classes)
    >
      <button
        on:click=move |_| set_classes(!classes)
      >
        Toggle
      </button>
    </div>
  }
}

This can be especially useful when using styling systems like Tailwind.

This was discussed in #2522.

[bicarlsen]

Another option is to use the current syntax, but split the class string at spaces.
e.g.

<div
  class=("class-1 class-2", true)
>
</div>

[gbj]

I like the array syntax a lot, and it seems to work in my testing. Thanks for this!