P2049 Constraint refinement for special-cased functions

[wg21bot]

P2049R0 Constraint refinement for special-cased functions (Andrew Sutton, Wyatt Childers)

[jfbastien]

Authors asked to delay this to next meeting.

[jfbastien]

Discussed here: https://wiki.edg.com/bin/view/Wg21prague/SG7notesP2049R0
According to author and the discussion, this paper is superseded by #603