Use pushStack in widget method. Fixes #5732 - make the widget method maintain the stack

ui/jquery.ui.autocomplete.js

@@ -311,7 +311,7 @@ $.widget( "ui.autocomplete", {
 	},
 
 	widget: function() {
-		return this.menu.element;
+		return this.element.pushStack(this.menu.element.get());
 	}
 });
 

ui/jquery.ui.button.js

@@ -210,7 +210,7 @@ $.widget( "ui.button", {
 	},
 
 	widget: function() {
-		return this.buttonElement;
+		return this.element.pushStack(this.buttonElement.get());
 	},
 
 	destroy: function() {

ui/jquery.ui.dialog.js

@@ -207,7 +207,7 @@ $.widget("ui.dialog", {
 	},
 
 	widget: function() {
-		return this.uiDialog;
+		return this.element.pushStack(this.uiDialog.get());
 	},
 
 	close: function(event) {

ui/jquery.ui.widget.js

@@ -160,7 +160,7 @@ $.Widget.prototype = {
 	},
 
 	widget: function() {
-		return this.element;
+		return this.element.pushStack(this.element.get());
 	},
 
 	option: function( key, value ) {