Better ring constructors #2959

Job	Run time
build (supported)	3m 34s
quick-build (supported, ubuntu-latest)	3m 13s
build (latest)	3m 25s
opam-build (supported, ubuntu-latest)	4m 46s
quick-build (latest, ubuntu-latest)	3m 8s
nix	2m 9s
build (dev, --warnings)	3m 19s
opam-build (latest, ubuntu-latest)	4m 38s
quick-build (dev, ubuntu-latest)	3m 18s
opam-build (dev, ubuntu-latest)	4m 26s
doc-alectryon	14m 58s
doc-dep-graphs	7m 19s
doc-coqdoc	1m 29s
coqchk (supported)	2m 9s
doc-timing	1m 40s
coqchk (latest)	2m 3s
install (supported)	1m 38s
coqchk (dev)	1m 45s
install (latest)	1m 41s
install (dev)	1m 46s
deploy-doc	0s
delete-artifacts	7s
	1h 12m 31s

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