Merge pull request #3337 from cal-itp/3336-bug-model-descripts-too-long

Shrunk descriptor of trip_start_time

warehouse/models/docs/gtfs rt/trip_descriptor.md

@@ -14,7 +14,7 @@ Caution: this field is still experimental, and subject to change. It may be form
 {% enddocs %}
 
 {% docs gtfs_trip_descriptor__start_time %}
-The initially scheduled start time of this trip instance. When the trip_id corresponds to a non-frequency-based trip, this field should either be omitted or be equal to the value in the GTFS feed. When the trip_id correponds to a frequency-based trip defined in GTFS frequencies.txt, start_time is required and must be specified for trip updates and vehicle positions. If the trip corresponds to exact_times=1 GTFS record, then start_time must be some multiple (including zero) of headway_secs later than frequencies.txt start_time for the corresponding time period. If the trip corresponds to exact_times=0, then its start_time may be arbitrary, and is initially expected to be the first departure of the trip. Once established, the start_time of this frequency-based exact_times=0 trip should be considered immutable, even if the first departure time changes -- that time change may instead be reflected in a StopTimeUpdate. If trip_id is omitted, start_time must be provided. Format and semantics of the field is same as that of GTFS frequencies.txt start_time, e.g., 11:15:35 or 25:15:35.
+Initially scheduled start time for a trip instance. For non-frequency-based trips, this field can be omitted or must match the GTFS feed. For frequency-based trips (defined in GTFS frequencies.txt), start_time is mandatory in trip updates and vehicle positions. If exact_times=1 in GTFS, start_time must be a multiple of headway_secs after the frequencies.txt start_time. If exact_times=0, the initial start_time is arbitrary but should then be considered fixed (updates reflected in StopTimeUpdate). Omitting trip_id requires providing start_time.  Use the same format as in GTFS frequencies.txt (e.g., 11:15:35).
 {% enddocs %}
 
 {% docs gtfs_trip_descriptor__start_date %}