Apply suggestions from code review

Co-authored-by: Richard Gibson <[email protected]>

Author: sffc

spec/abstractops.html

@@ -557,8 +557,7 @@ <h1>
     </dl>
     <p>Both singular and plural unit names are accepted, but only the singular form is used internally.</p>
     <emu-alg>
-      1. Let _allowedStrings_ be a new empty List.
-      1. Append *"auto"* to _allowedStrings_.
+      1. Let _allowedStrings_ be « *"auto"* ».
       1. For each row of <emu-xref href="#table-temporal-units"></emu-xref>, except the header row, in table order, do
         1. Let _singularName_ be the value in the "Singular property name" column of the row.
         1. Append _singularName_ to _allowedStrings_.
@@ -589,14 +588,11 @@ <h1>
       <dd>It validates that the result of GetTemporalUnitValuedOption is <emu-not-ref>covered</emu-not-ref> by the union of _unitGroup_ and _extraValues_.</dd>
     </dl>
     <emu-alg>
-      1. Let _allowedValues_ be a new empty List.
-      1. For each row of <emu-xref href="#table-temporal-units"></emu-xref>, except the header row, in table order, do
-        1. Let _unit_ be the value in the "Value" column of the row.
-        1. If the "Category" column of the row is ~date~ and _unitGroup_ is ~date~ or ~datetime~, append _unit_ to _allowedValues_.
-        1. Else if the "Category" column of the row is ~time~ and _unitGroup_ is ~time~ or ~datetime~, append _unit_ to _allowedValues_.
-      1. If _extraValues_ is present, then
-        1. Set _allowedValues_ to the list-concatenation of _allowedValues_ and _extraValues_.
-      1. If _allowedValues_ does not contain _value_, throw a RangeError exception.
+      1. If _extraValues_ is present and _extraValues_ contains _value_, return ~unused~.
+      1. Let _category_ be the value in the “Category” column of the row of <emu-xref href="#table-temporal-units"></emu-xref> whose “Value” column contains _value_. If there is no such row, throw a RangeError exception.
+      1. If _category_ is ~date~ and _unitGroup_ is ~date~ or ~datetime~, return ~unused~.
+      1. If _category_ is ~time~ and _unitGroup_ is ~time~ or ~datetime~, return ~unused~.
+      1. Throw a RangeError exception.
     </emu-alg>
   </emu-clause>