doc: Explain why tryEval does not return the message #13999

Job	Run time
tests on ubuntu	27m 27s
Check Docker secrets present for installer tests	1s
tests on macos	20m 49s
eval	53s
meson_build (ubuntu-latest)	3m 29s
meson_build (macos-latest)	2m 49s
vm_tests	21m 31s
flake_regressions	34m 1s
installer test on ubuntu	38s
installer test on macos	1m 22s
docker_push_image	0s
	1h 53m 0s

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