docs: change the `ExperimentalFeatures.DTO_CODEGEN` description #4180

Job	Run time
pyright	1m 59s
mypy	2m 16s
slotscheck	1m 36s
Test server integration (uvicorn<0.27.0)	1m 35s
Test Minimal Application with Base Dependencies	1m 18s
Test server integration (uvicorn>=0.27.0)	1m 37s
validate	24s
Test Minimal Pydantic 1 application	1m 37s
test-platform-compat	0s
test (3.10) / test	2m 53s
test (3.11) / test	2m 33s
test (3.12) / test	3m 52s
test (3.8) / test	3m 40s
test (3.9) / test	2m 58s
build-docs	3m 32s
codeql	2m 58s
sonar	1m 20s
upload-test-coverage	18s
	36m 26s

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