GeoCSV example in fdsnws-availabilty spec document shows irisws implementation

[nick-falco]

The example titled "Requesting extents in GeoCSV format" in the documentation shows field names that follow the "irisws" implementation of GeoCSV, not the "fdsnws" implementation.

Requesting extents in GeoCSV format:

https://DataCenter/fdsnws/availability/1/extent?format=geocsv&network=IU&station=ANMO&channel=BHZ

#dataset: GeoCSV 2.0
#delimiter: |
#field_unit: unitless|unitless|unitless|unitless|unitless|hertz|ISO_8601|ISO_8601|ISO_8601|unitless|unitless
#field_type: string|string|string|string|string|float|datetime|datetime|datetime|integer|string
network|station|location|channel|quality|sample_rate|earliest|latest|updated|timespans|restriction
IU|ANMO||BHZ|M|20.0|1989-08-29T22:07:20.482000Z|1998-10-26T17:38:43.640000Z|2018-05-08T21:47:09Z|611|OPEN
IU|ANMO|00|BHZ|M|0.0|2002-08-28T18:17:51.000000Z|2008-05-23T23:09:24.000000Z|2017-12-06T03:42:35Z|9051|OPEN
IU|ANMO|00|BHZ|M|20.0|1998-10-26T20:35:58.310000Z|2018-07-09T20:45:47.369000Z|2018-07-10T08:29:54Z|2238|OPEN
IU|ANMO|00|BHZ|M|40.0|2018-07-09T20:46:40.594000Z|2019-04-02T23:59:59.994000Z|2019-04-03T08:27:06Z|4|OPEN
IU|ANMO|10|BHZ|M|0.0|2002-11-28T04:00:00.000000Z|2007-06-01T19:29:00.000000Z|2017-12-06T03:09:51Z|47|OPEN
IU|ANMO|10|BHZ|M|40.0|1998-10-26T20:35:59.072000Z|2019-04-02T23:59:59.994000Z|2019-04-03T08:27:06Z|180|OPEN