doc: exclude doc updates from CHANGELOG #569

Job	Run time
clippy	25s
Checking fmt and docs	24s
Build and test: ubuntu-latest, stable	47s
Build and test: ubuntu-latest, nightly	49s
fuzz_read	3h 21m 34s
fuzz_read_with_no_features	2h 52m 56s
Build and test: ubuntu-latest, msrv	1m 1s
Build and test: macOS-latest, stable	1m 17s
Build and test: macOS-latest, nightly	2m 19s
fuzz_write_with_no_features	27m 49s
Build and test: macOS-latest, msrv	3m 1s
fuzz_write	3h 15m 10s
Build and test: windows-latest, stable	2m 25s
Build and test: windows-latest, nightly	2m 27s
Release-plz	5m 7s
Build and test: windows-latest, msrv	1m 38s
	10h 19m 9s

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