Add Rawf, remove some useless components

⚠️ BREAKING: This release removes the high-level helper components InputHidden, LinkStylesheet, and LinkPreload that no-one was using, including myself. If anyone needs them back, here they are:

func InputHidden(name, value string, children ...g.Node) g.Node {
 	return Input(Type("hidden"), Name(name), Value(value), g.Group(children))
}

func LinkStylesheet(href string, children ...g.Node) g.Node {
	return Link(Rel("stylesheet"), Href(href), g.Group(children))
}

func LinkPreload(href, as string, children ...g.Node) g.Node {
	return Link(Rel("preload"), Href(href), As(as), g.Group(children))
}

This release also adds a new Rawf function, that is like Raw but interpolates the given string like Textf. Use with care.

Also, added an EncType html attribute component.