Embedding static html.

The type argument Never in Html Never tells us that the html has no event handlers attached, it will not generate any messages. We may want to embed such static html into arbitrary views, while using types to enforce the staticness. That is what this function provides.

Note: To call this function, the argument need not be literally of type Html Never. It suffices if it is a fully polymorphic (in the message type) Html value. For example, this works: static (Html.text "abcdef").