private static boolean isHexDigit(char c) {
		return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F');
	}
Returns a possible suffix
@return the suffix or {@code null}
Ghidra/Features/MicrosoftDmang/src/main/java/mdemangler/datatype/modifier/MDQuestionModifierType.java