Cylc-flow: Warn the user if the stop CP is never going to be used

[kinow]

Describe exactly what you would like to see in an upcoming release

If you have a start CP 1, and final CP 2, and define stop CP as 100, your stop CP is just going to be ignored and never used. It would be helpful to users to log a warning.

rm -rf .service && cylc play --no-detach five --initial-cycle-point=1 --final-cycle-point=2 --stop-cycle-point=4

Additional context

From General element chat room.

Pull requests welcome!

[MetRonnie]

Best place to put this check is probably in
https://github.com/cylc/cylc-flow/blob/87e22ab623ccccb48f990dd9d64357453c1c8a56/cylc/flow/scheduler.py#L1868

Side note: maybe that method should be moved into cylc.flow.config.WorkflowConfig where the rest of the process_*_point methods are? Although it could be that there is something preventing it

[oliver-sanders]

warning: --stop-cycle-point=<stop-cycle-point> ignored because it is after the final cycle point (<final-cycle-point>)