[DOC] - SWML Core Concepts missing from tech ref #757
Description
Describe the requested update
Certain core concepts version, section, main, do not have technical reference pages.
Reason for the request
These should be present in the tech ref portion of the SWML documentation and not solely in the overview. It allows for situations where users can be confused as there is no set page for these parameters to be defined. If they do not see the definition in the overview they may not know what these are.
Sections to be updated
https://developer.signalwire.com/swml
Additional context
Leaning towards 1 page, the same way we do for Variables.