Moving issue# 894 EnumerationValue along

I am very interested in moving along the EnumerationValue proposal for
markup of external enumerations outlined in issue #894 [1] and pull request
#924 [2]. I had hoped to see it in the last release cycle, but it was not.

Dan, you said with regard to pull request #924:

"I'll try to draw wider attention to it in the next release cycle. It's the
kind of thing that needs serious and focused attention as it has impact
across the entire project."

So maybe we can start that "serious and focused attention" now?

Stuart

[1] https://github.com/schemaorg/schemaorg/issues/894
[2] https://github.com/schemaorg/schemaorg/pull/924