public static Icon makeTransparent(Icon icon) {
		return makeTransparent(icon, DEFAULT_TRANSPARENCY_ALPHA);
	}
Make the specified icon semi-transparent using the default transparency alpha
@param icon The icon to make semi-transparent
@return a new icon, based on the original, made semi-transparent
@see ImageUtils#DEFAULT_TRANSPARENCY_ALPHA
Ghidra/Framework/Gui/src/main/java/generic/util/image/ImageUtils.java