feat: add dangerouslySetInnerHTML attr

This adds are new attribute to Elements, "dangerouslySetInnerHTML", which like the same attribute from React allows one to take a stirng of unescaped HTML and render it unconditionally. This is of course a potentially dangerous operation that can open your app up to XSS attacks, but for interoperating with existing content management systems and libraries that output HTML (e.g. markdown renderers).

Using "dangerouslySetInnerHTML" on an element with children will generate an error within createElement, since it doesn't make sense to have both children and inner HTML.

src/jsx.ts

@@ -25,7 +25,14 @@ export interface MicrodataAttributes {
     itemRef?: string;
 }
 
-export interface HTMLAttributes extends RdfaAttributes, MicrodataAttributes {
+export interface SetInnerHtmlAttributes {
+    dangerouslySetInnerHTML?: { __html: string };
+}
+
+export interface HTMLAttributes
+    extends RdfaAttributes,
+        MicrodataAttributes,
+        SetInnerHtmlAttributes {
     accept?: string;
     acceptCharset?: string;
     accessKey?: string;