Refactored widget renderers to be hosted within HTML element renderers

This arrangement takes better advantage of the similarities between the
now deleted widget renderer and the element renderer. It also obviates
the need for wrapper elements around every widget.

core/modules/parsers/wikiparser/rules/transcludeinline.js

@@ -40,8 +40,8 @@ exports.parse = function() {
 		classes = this.match[5];
 	// Return the transclude widget
 	var node = {
-		type: "widget",
-		tag: "transclude",
+		type: "element",
+		tag: "$transclude",
 		attributes: {
 			target: {type: "string", value: targetTitle}
 		}