clarity on x-extensible-enum usage for events

[a1exsh]

When I think about it, the x-extensible-enum gives a stronger signal to the event publishers: namely, the set of currently accepted values.

For the event consumers, in turn, it only signifies the list of currently most commonly found values, but does not restrict the future or the past set of possible values in any way. In that regard it's not much different from a free-form string with examples provided.

[a1exsh]

:+1:

[tkrop]

👍

[ePaul]

@tfrauenstein wanted to extend the PR as discussed in the Meeting (internal link)

[tfrauenstein]

done

[tfrauenstein]

👍

[tkrop]

👍