docs: Fix IETF reference (#4011) #4807

Job	Run time
mypy	1m 1s
pyright	38s
slotscheck	18s
validate	17s
Test server integration (uvicorn<0.27.0)	44s
Test server integration (uvicorn>=0.27.0)	38s
Test Minimal Application with Base Dependencies	20s
Test Minimal Pydantic 1 application	35s
test (3.10) / test	1m 46s
test (3.11) / test	1m 50s
test (3.12) / test	3m 2s
test (3.13) / test	1m 48s
test (3.8) / test	2m 52s
test (3.9) / test	1m 56s
test-platform-compat (macos-latest) / test	1m 16s
test-platform-compat (windows-latest) / test	5m 15s
build-docs	0s
codeql	2m 9s
sonar	1m 28s
upload-test-coverage	17s
	28m 10s

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