Return the abbreviated character‐string representation of the enumerator corresponding to the specified dayOfWeek. This representation matches the enumerator's three‐character name (e.g., e_SUN) with the "e_" prefix elided. For example: ` bsl::cout << bdlt::DayOfWeek::toAscii(bdlt::DayOfWeek::e_SUN); ` prints the following on standard output: ` SUN ` Note that specifying a dayOfWeek that does not match any of the enumerators will result in an unspecified string representation being returned that is distinct from the values returned for any valid enumeration.