Associativity of Join, and lots more #1590

Job	Run time
nix	4m 39s
quick-build (supported, ubuntu-latest)	3m 25s
build (supported)	3m 49s
quick-build (latest, ubuntu-latest)	4m 0s
opam-build (supported, ubuntu-latest)	7m 13s
build (latest)	4m 20s
quick-build (dev, ubuntu-latest)	4m 35s
opam-build (8.17, ubuntu-latest)	6m 33s
build (dev, --warnings)	3m 36s
opam-build (latest, ubuntu-latest)	5m 19s
opam-build (dev, ubuntu-latest)	5m 30s
doc-coqdoc	1m 2s
doc-dep-graphs	8m 23s
doc-alectryon	15m 3s
coqchk (supported)	2m 22s
doc-timing	1m 26s
coqchk (latest)	1m 58s
install (supported)	1m 11s
coqchk (dev)	1m 42s
install (latest)	1m 32s
install (dev)	1m 13s
deploy-doc	0s
delete-artifacts	9s
	1h 29m 0s

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