UI: Update text for custom browser dock menu items manually

Instead of relying on the dock's having their window title already set
for the menu items to be updated, let's just manually update the menu
item text ourselves when updating the item.

UI/window-extra-browsers.cpp

@@ -180,6 +180,7 @@ void ExtraBrowsersModel::UpdateItem(Item &item)
 
 	if (main->extraBrowserDockNames[idx] != item.title) {
 		main->extraBrowserDockNames[idx] = item.title;
+		dock->toggleViewAction()->setText(item.title);
 	}
 
 	if (main->extraBrowserDockTargets[idx] != item.url) {