test

`RuleBuilder#numberize_references` should check LHS and RHS for duplication #1069

Job	Run time
check-misc (head)	14s
steep-check (head)	24s
test-memory (head)	28s
test-ruby (head, master)	5m 12s
test-ruby (3.0, master)	5m 24s
test-ruby (2.7, master)	5m 40s
test-windows (head)	1m 44s
ruby-versions / Generate Ruby versions	3s
test (2.5)	29s
test (2.6)	24s
test (2.7)	23s
test (3.0)	13s
test (3.1)	15s
test (3.2)	9s
test (3.3)	21s
test (head)	10s
	21m 33s

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