Adds <=> across the standard library ('the mothership').
Other papers in Three-way comparison (<=>)
P0515R3Consistent comparisonAlbuquerque 2017P0768R1Library support for the spaceship (comparison) operatorAlbuquerque 2017P0905R1Symmetry for spaceshipJacksonville 2018P1120R0Consistency improvements for
<=> and other comparison operatorsRapperswil 2018P1185R2<=> != ==Kona 2019P1186R3When do you actually use <=>?Cologne 2019All 13 papers in Three-way comparison (<=>) →