editorial: cleanup table 1

[ryzokuken]

Clean up Table 1, reducing it to only include fields absolutely necessary for operation.

Fixes: https://github.com/tc39/proposal-intl-duration-format/issues/135

[FrankYFTang]

I see a conflict between this and #138 . Which one should we keep? @ben-allen @sffc

[ben-allen]

138 works by splitting the big table up by placing components of it in separate tables relevant to specific operations, this one works by removing NumberFormat Unit, Values, and Digital Default from Table 1 and then computing them as needed. I have a mild preference for #138 since to my eye it provides better documentation, but some may feel that having two tables with incomplete lists of Internal Slots is deceptive.