P3695 R1 Deprecate implicit conversions between Unicode character types

[wg21bot]

P3695R0 Deprecate implicit conversions between Unicode character types (Jan Schultke)

[erichkeane]

SG16 should see first, then EWG chairs will decide on EWGI vs EWG.

[wg21bot]

P3695R1 Deprecate implicit conversions between Unicode character types (Jan Schultke)