Fix documentation of dirty and mark_dirty functions #2356

Job	Run time
Test Suite [no features]	1m 55s
Test Suite [default features]	1m 54s
Build [debug feature]	38s
Test Suite [default except content_size]	1m 55s
Test Suite [std + block)]	2m 3s
Test Suite [default + serde]	2m 5s
Test Suite [std + flexbox]	2m 3s
Test Suite [std + grid]	2m 1s
Test Suite [alloc + no algorithms]	2m 1s
MSRV Build [Rust 1.65]	1m 41s
Test Suite [std (no algorithms)]	2m 3s
Build Benchmarks	1m 2s
Build Benchmarks (w/ yoga)	1m 14s
Clippy	1m 19s
Documentation	52s
Test Fixture Formatting	37s
Rustfmt	11s
Markdown Lint	5s
Test Suite [alloc + all algorithms]	2m 6s
	27m 45s

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