refactor: remove class name sanitization, since CSS class names are already HTML attribute escaped

[a-h]

Fixes #211

[gungun974]

This PR is good.
I think it's still good to keep some form of sensitization (even if indirect) for security.

The only concern here I don't see any test testing some TailwindCSS syntax.

In Tailwind for example we use a lot of of closse with - and : like hover:bg-sky-700.
And even sometime thing like text-[#50d71e] or even w-[calc(100%-4rem) with the JIT.

I can suggest to be sure add some complex Class name in the generator test-css-usage tests.

[oliverpool]

I suggest adding the following tests:

templ TailwindClasses() {
	<button class={ "hover:bg-sky-700", "text-[#50d71e]", "w-[calc(100%-4rem)]" }>Tailwind classes</button>
}

templ EscapedClasses() {
	<button class={ "<script>", "\" href=\"#hacked" }>Escaped classes</button>
}

...


	{! TailwindClasses() }
	{! EscapedClasses() }

It seems that the htmldiff.Diff is hiding some escaping.
I added the unescaped HTML to generator/test-css-usage/expected.html

<button class="<script> " href="#hacked">Escaped classes</button>

and the test passes !

However the actually generated HTML is more like

<button class="&lt;script&gt; &#34; href=&#34;#hacked">Escaped classes</button>

I think the bug lies in https://github.com/a-h/htmlformat

 // < & co. gets wrongly removed
htmlformat.Fragment(&buf, strings.NewReader(`<button class="&lt;script&gt; &#34; href=&#34;#hacked">Escaped classes</button>`))