multi: fix `staticcheck` flags #2829

Job	Run time
SQL compilation check	8s
verify that auto-generated documentation is up-to-date	31s
RPC compilation check	1m 47s
run LiT unit tests	6m 32s
build and lint code	4m 59s
run unit-test postgres race	10m 25s
go mod check	11m 17s
run unit-test sqlite3 race	9m 30s
run LiT itests	3m 56s
	49m 5s

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