Review forecast proposal / snapshot endpoint documentation for clarity and correctness

[caindy]

No description provided.

[catkins-miso]

In a discussion with a vendor yesterday and responding to a TO in a separate email, this scenario came up:

Scenario: Temporary AAR exception clashes with telemetered

Given Ratings Provider has previously submitted a Temporary AAR Exception for a particular segment
When the Ratings Provider successfully submits a Ratings Forecast for the current Forecast Window for that segment
And the forecasted value clashes (higher or lower) with the exception value
Then the TROLIE proposal uses the Ratings Forecast value not the Exception value
And the response indicates the Temporary AAR exception clashed

Do you think we should nail down this scenario before completing the milestone?