Add ~unset~ to allowed values

Author: sffc

spec/abstractops.html

@@ -1864,7 +1864,7 @@ <h1>
     <emu-alg>
       1. NOTE: The following steps read options and perform independent validation in alphabetical order.
       1. Let _largestUnit_ be ? GetTemporalUnitValuedOption(_options_, *"largestUnit"*, ~unset~).
-      1. Perform ? ValidateTemporalUnitValue(_largestUnit_, _unitGroup_).
+      1. Perform ? ValidateTemporalUnitValue(_largestUnit_, _unitGroup_, « ~unset~ »).
       1. If _largestUnit_ is ~unset~, then
         1. Set _largestUnit_ to ~auto~.
       1. If _disallowedUnits_ contains _largestUnit_, throw a *RangeError* exception.
@@ -1873,7 +1873,7 @@ <h1>
       1. If _operation_ is ~since~, then
         1. Set _roundingMode_ to NegateRoundingMode(_roundingMode_).
       1. Let _smallestUnit_ be ? GetTemporalUnitValuedOption(_options_, *"smallestUnit"*, ~unset~).
-      1. Perform ? ValidateTemporalUnitValue(_smallestUnit_, _unitGroup_).
+      1. Perform ? ValidateTemporalUnitValue(_smallestUnit_, _unitGroup_, « ~unset~ »).
       1. If _smallestUnit_ is ~unset~, then
         1. Set _smallestUnit_ to _fallbackSmallestUnit_.
       1. If _disallowedUnits_ contains _smallestUnit_, throw a *RangeError* exception.