Ensure list widget item title is used in getStateQualifier

Resolves a longstanding problem where the same state qualifier is
generated for every member of a list.

Fixes #2628

core/modules/widgets/list.js

@@ -305,6 +305,8 @@ Compute the internal state of the widget
 ListItemWidget.prototype.execute = function() {
 	// Set the current list item title
 	this.setVariable(this.parseTreeNode.variableName,this.parseTreeNode.itemTitle);
+	// Make sure the item title is used by widget.getStateQualifier()
+	this.setVariable("transclusion","{" + this.parseTreeNode.itemTitle + "}");
 	// Construct the child widgets
 	this.makeChildWidgets();
 };