Special characters, the class directive and scoped css

[mrkishi]

REPL

Currently, we can already use special characters in class names:

<element class="some:name" class:another:name={enabled}>Hello world</element>

Both of these will be added to the element correctly.

However, the ones added with the class: directive won't get properly scoped. Given:

<style>
    .some\:name { ... }
    .another\:name { ... }
</style>

The first selector will be scoped and included, while the second will be dropped with an Unused CSS selector warning.