Fields and slots should be eligible for ecmarkup interactive highlighting

[gibson042]

As noted in tc39/proposal-temporal#2290 (review) :

The sticky highlighting becomes less useful [for Record fields than for aliases]. When auditing the uses of BalanceDuration, for example, I found it a lifesaver to be able to highlight years, months, weeks, days, etc. in different colors. If they become durationFieldsRecord.[[Years]] etc., that's no longer possible.

I think fields and slots should participate in interactive highlighting, or at least be eligible, which requires them to have distinct parse nodes here.