Improve Documentation: `decreasing_or_equal_stop_time_distance` explanatory text.

[uq-bfitzpatrick]

Hello,

If I have understood it correctly, I think that the explanation of this error in RULES.md could be improved.

This error seems to refer to fields expected in the file stop_times.txt rather than in the file stops.txt. Consequently, the entry under References in RULES.md for this error could be updated to stop_times.txt.

This error seems to refer to the expected fields stop_sequence and shape_dist_traveled in the file stop_times.txt. If so, the text explaining this error in RULES.md could be updated to include these field names for increased clarity.

That is, in the text:

"When sorted by stop_times.stop_pt_sequence, two consecutive stop times in a trip should have increasing distance. If the values are equal, this is considered as an error."

stop_times.stop_pt_sequence could be updated to stop_times.stop_sequence to match the specification here: https://gtfs.org/schedule/reference/#stop_timestxt

and

the phrase 'should have increasing distance' could be updated to refer to the field shape_dist_traveled by name.

Also, given that each row of stop_times.txt contains both an arrival_time and a departure_time, perhaps it would be clearer to refer to consecutive entries in this file rather than "consecutive stop times".

I think these changes would make the description of this error easier to understand.

Thanks again for this very useful tool.

[isabelle-dr]

Hello @uq-bfitzpatrick, thank you for opening this issue 😊. I have modified the reference file and the non-existent stop_pt_sequence field in #1234. The last part is modifying the text to make it more clear, do you have a proposition for the definition you wish were there when you saw the issue the first time?

Thanks