default void addHeader(@Nonnull ContextMenu menu, @Nullable String title, @Nullable Node graphic) {
		MenuItem header = new MenuItem(title, graphic);
		menu.getItems().add(header);
	}
Add a header item to the given menu.

@param menu
		Menu to add to.
@param title
		Header text content.
@param graphic
		Header graphic.
recaf-ui/src/main/java/software/coley/recaf/services/cell/context/ContextMenuProviderFactory.java