Constant margin_width

pub const margin_width: AttributeDescription;

Usage in rsx

let margin_width = "value";

rsx! {
    // Attributes need to be under the element they modify
    iframe {
        // Attributes are followed by a colon and then the value of the attribute
        margin_width: "value"
    }
    iframe {
        // Or you can use the shorthand syntax if you have a variable in scope that has the same name as the attribute
        margin_width,
    }
};