behavior/docs of iCalendar export

[Carson Chittom]

This is a very small thing, but it came up today for me, so I thought I'd 
mention it. (Org 9.4.2, for the record.)

I've just started playing with the iCalendar export because eventually I want 
to keep everything in Org, to then get transformed and pushed to my CalDAV 
server, which then gets pushed to my phone.  

So after reading the docs[1][2] I created a minimal org file, which as it 
happens only had a single time for the single event in it.  I tried to export 
via C-c C-e c f, and immediately got an error that 
org-agenda-default-appointment-duration wasn't set (which was perfectly true, I 
hadn't set it and it defaults to nil).  So after looking at that variable's 
documentation, just to make sure it was well-named and didn't do something 
strange, I set it and went on about my merry way.  As I say, a very small 
thing. I mention it only because it was slightly irritating that after actually 
taking the time to read the documentation, I still had to troubleshoot (if you 
want to call it that) briefly. 

All of which leads up to: my suggestion is that either that 
org-agenda-default-appointment-duration have an actual default value, or else 
that [2] should mention that one might want to set it.  


[1] https://orgmode.org/manual/Timestamps.html#Timestamps
[2] https://orgmode.org/manual/iCalendar-Export.html