[draft] trying to warn about too big segment depth change

[GitPaean]

it will give warning for every report step, which is not desirable. Will look for other approaches.

[GitPaean]

probably we should warn based on keyword level, obstacle is that what if the information is not completed for now. Will look into it. probably can be done after each keyword input, to see if found anything not right onsite.

The goal is to give warning once per parsing of the schedule, while not repeated.