Update calendar documentation

Also remove the link to the religious events calendar - it's not being maintained

Author: graeme-a-stewart

calendar.md

@@ -5,8 +5,11 @@ layout: default
 ---
 
 The HSF [Community Calendar](https://calendar.google.com/calendar/embed?src=e4v33e1a1drbncdle1n03ahpcs%40group.calendar.google.com){:target="_hsf_calendar"}
-can be edited by people in the [HSF Coordination Team](https://groups.google.com/forum/#!forum/hsf-coordination)
-or in the [HSF Calendar Editors Group](https://groups.google.com/forum/#!forum/hsf-calendar-editors) Google Groups.
+can be edited by people in the following Google Groups:
+
+- [HSF Steering Group](https://groups.google.com/forum/#!forum/hsf-steering)
+- [HSF Working Group Conveners](https://groups.google.com/forum/#!forum/hsf-wg-conveners)
+- [HSF Calendar Editors Group](https://groups.google.com/forum/#!forum/hsf-calendar-editors) Google Groups.
 
 The most straight forward way to do this is to 
 
@@ -22,4 +25,4 @@ Then you will have the ability to view events in the community calendar and, if
 
 Please ask to join one of the editing groups if you would like to add events
 for your experiment or community.
-Events in HSF working groups indico categories should be synced automatically. 
+Events in HSF working groups indico categories should be synced automatically.

future-events.md

@@ -8,6 +8,3 @@ layout: plain
 - To add this calendar to your own setup, use this [ical link](https://calendar.google.com/calendar/ical/e4v33e1a1drbncdle1n03ahpcs%40group.calendar.google.com/public/basic.ics). You can also view the [Standalone calendar page](https://calendar.google.com/calendar/embed?src=e4v33e1a1drbncdle1n03ahpcs%40group.calendar.google.com&ctz=Europe/Amsterdam).
 
 - If you would like an event added to the calendar, please contact the [HSF Coordination Group](mailto:hsf-coordination@googlegroups.com) (we can grant [editing rights]({{ site.baseurl }}/calendar.html) where appropriate).
-
-- If you are planning a meeting and want to ensure that you also don't clash with major religious holidays
-there is a [calendar maintained by the community]({{ site.baseurl }}/holiday-calendar.html) that lists these.