add Attempt monad #277

Job	Run time
CS (8.2)	28s
BlackBox (ubuntu-latest, 8.2, lowest)	1m 17s
Psalm (8.2)	16s
BlackBox (ubuntu-latest, 8.2, highest)	1m 25s
Coverage (ubuntu-latest, 8.2, lowest)	4m 27s
Psalm (8.3)	16s
BlackBox (ubuntu-latest, 8.3, lowest)	1m 28s
Coverage (ubuntu-latest, 8.2, highest)	4m 23s
BlackBox (ubuntu-latest, 8.3, highest)	1m 21s
Coverage (ubuntu-latest, 8.3, lowest)	4m 19s
BlackBox (macOS-latest, 8.2, lowest)	2m 28s
Coverage (ubuntu-latest, 8.3, highest)	4m 22s
BlackBox (macOS-latest, 8.2, highest)	2m 5s
Coverage (macOS-latest, 8.2, lowest)	4m 7s
BlackBox (macOS-latest, 8.3, lowest)	2m 16s
Coverage (macOS-latest, 8.2, highest)	3m 37s
BlackBox (macOS-latest, 8.3, highest)	2m 11s
Coverage (macOS-latest, 8.3, lowest)	4m 9s
Coverage (macOS-latest, 8.3, highest)	4m 36s
	49m 31s

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