Fix rsx rosetta element and attribute mapping

[ealmloff]

This PR changes rsx-rosetta to use the mapping of html->rsx names for elements and attributes defined in dioxus-html instead of converting the case of the attributes and elements.

This fixes the following cases:

• translating h1-h6

old:

h_1 {}

new:

h1 {}

• translating web components

old:

my_component {}

new:

my-component {}

• translating unsupported attributes

old:

div { unrecognizedattribute: "asd", "hello world" }

new:

div { "unrecognizedattribute": "asd", "hello world" }

[jkelleyrtp]

Sweet, thanks!