Domain membership wording looks wrong

[deeglaze]

Endorsed environments (Section 5.1.4.3) membership is conditional upon successful matching of Reference Values (Section 5.1.4.2) to Evidence.

I don't think we have a sense of which reference values an environment is supposed to match before suggesting that its within a particular trust domain. We got rid of the wording of matching reference values for endorsed triples for this reason.