Update CallScreeningService API docs.

Cleanup some formatting issues.
Update the docs to more clearly indicate what data will be passed
to the CallScreeningService about a call.
Update the docs to clearly indicate the new behavior for setSkipCallLog
with respect to logging of calls.

Bug: 63966743
Test: API doc only change; build.
Change-Id: I5daeea32f6cfbef1b94105a826925a878ac98596