nats: De/Ser using `sample_freq` instead of `sample_frequency` #4395

Job	Run time
check docs (ubuntu-latest / stable)	1m 9s
test (ubuntu-latest / stable)	7m 11s
test (macos-latest / stable)	8m 12s
check examples (ubuntu-latest / stable)	1m 41s
check feature flags (ubuntu-latest / stable)	9m 42s
check format (ubuntu-latest / nightly)	50s
test (windows-latest / stable)	11m 14s
check licenses (ubuntu-latest / stable)	32s
check linter (ubuntu-latest / stable)	1m 19s
check minimal versions of transitive dependencies (ubuntu-latest / stable)	26s
check minimal supported rust version (ubuntu-latest / msrv)	27s
check spelling (ubuntu-latest / nightly)	40s
	43m 23s

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