Add `Enumerable#find_value` #12055

Job	Run time
check_format	1m 33s
deploy_api_docs	0s
x86_64-gnu-test (1.7.3)	34m 9s
x86_64-gnu-test-preview_mt	5m 55s
x86_64-gnu-test (1.8.2)	35m 52s
x86_64-musl-test	36m 31s
x86_64-gnu-test (1.9.2)	34m 11s
x86_64-gnu-test (1.10.1)	34m 5s
x86_64-gnu-test (1.11.2)	35m 32s
x86_64-gnu-test (1.12.2)	34m 50s
x86_64-gnu-test (1.13.1)	34m 31s
x86_64-gnu-test (1.0.0, FLAGS=-Dwithout_ffi USE_PCRE1=true)	33m 13s
x86_64-gnu-test (1.1.1, FLAGS=-Dwithout_ffi USE_PCRE1=true)	36m 37s
x86_64-gnu-test (1.2.2, USE_PCRE1=true)	35m 29s
x86_64-gnu-test (1.3.2, USE_PCRE1=true)	34m 13s
x86_64-gnu-test (1.4.1, USE_PCRE1=true)	35m 27s
x86_64-gnu-test (1.5.1, USE_PCRE1=true)	34m 25s
x86_64-gnu-test (1.6.2, USE_PCRE1=true)	34m 3s
	8h 50m 36s

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