docs: fix a typo in `requests` usage docs #4163

Job	Run time
pyright	1m 58s
slotscheck	1m 31s
mypy	2m 13s
Test server integration (uvicorn<0.27.0)	1m 39s
Test Minimal Application with Base Dependencies	1m 26s
Test Minimal Pydantic 1 application	1m 29s
Test server integration (uvicorn>=0.27.0)	1m 41s
test-platform-compat	0s
validate	24s
test (3.10) / test	2m 43s
test (3.11) / test	2m 23s
test (3.12) / test	3m 47s
test (3.8) / test	3m 52s
test (3.9) / test	2m 54s
build-docs	3m 27s
upload-test-coverage	22s
codeql	3m 2s
sonar	59s
	35m 50s

Provide feedback