Remove JMAP-specific text from JSCalendar regos

The registration should be about what it means in the JSCalendar
context. The effect within JMAP is already defined in the ACLs
description earlier in the doc.

rfc/src/calendars.xml

@@ -486,15 +486,13 @@ invitation from another calendar system)? This is true if, and only if:</t>
 <section anchor="mayinviteself"><name>mayInviteSelf</name>
 <t>Type: <tt>Boolean</tt> (default: false)</t>
 <t>Context: Event, Task</t>
-<t>If true, any user may add themselves to the event as a participant with the "attendee" role. This property MUST NOT be altered in the recurrenceOverrides; it may only be set on the base object.</t>
-<t>This indicates the event will accept "party crasher" RSVPs via iTIP, subject to any other domain-specific restrictions, and users may add themselves to the event via JMAP as long as they have the mayRSVP permission for the calendar.</t>
+<t>If true, anyone may add themselves to the event as a participant with the "attendee" role. This property MUST NOT be altered in the recurrenceOverrides; it may only be set on the base object.</t>
 </section>
 
 <section anchor="mayinviteothers"><name>mayInviteOthers</name>
 <t>Type: <tt>Boolean</tt> (default: false)</t>
 <t>Context: Event, Task</t>
 <t>If true, any current participant with the "attendee" role may add new participants with the "attendee" role to the event. This property MUST NOT be altered in the recurrenceOverrides; it may only be set on the base object.</t>
-<t>The mayRSVP permission for the calendar is also required in conjunction with this event property for users to be allowed to make this change via JMAP.</t>
 </section>
 
 <section anchor="hideattendees"><name>hideAttendees</name>