P2046 Rangify New Algorithms

[wg21bot]

P2046R0 Rangify New Algorithms (Dan Raviv)

[JeffGarland]

A modified form of this paper was moved by LWG in Prague for c++20

[JeffGarland]

reopen for project editor - removing lwg tag

[jensmaurer]

Applied P1243R4 Rangify New Algorithms in Prague.