Editorial: Fix PlainYearMonth.prototype.daysInYear return value

Author: linusg

spec/plainyearmonth.html

@@ -187,7 +187,7 @@ <h1>get Temporal.PlainYearMonth.prototype.daysInYear</h1>
       <emu-alg>
         1. Let _yearMonth_ be the *this* value.
         1. Perform ? RequireInternalSlot(_yearMonth_, [[InitializedTemporalYearMonth]]).
-        1. Return 𝔽(CalendarISOToDate(_yearMonth_.[[Calendar]], _yearMonth_.[[ISODate]]).[[Day]]).
+        1. Return 𝔽(CalendarISOToDate(_yearMonth_.[[Calendar]], _yearMonth_.[[ISODate]]).[[DaysInYear]]).
       </emu-alg>
     </emu-clause>