Loosen type restriction on to_contain #89

Job	Run time
build-and-test (native, windows-latest)	2m 7s
build-and-test (native, ubuntu-latest)	49s
build-and-test (native, macos-15)	31s
build-and-test (llvm-18, macos-13)	1m 52s
build-and-test (gcc-14, macos-13)	1m 51s
build-and-test (llvm-18, ubuntu-latest)	54s
build-and-test (gcc-14, ubuntu-latest)	49s
build-and-test (gcc-14, macos-15)	43s
build-and-test (llvm-18, macos-15)	38s
build-and-test (llvm-18, windows-latest)	2m 22s
Publish Tests Results	10s
	12m 46s

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