Tests

gh-137952: update `csv.Sniffer().has_header()` docs to describe the actual off-by-onish behavior #173202

Job	Run time
Change detection / Create context from changed files	13s
Ubuntu SSL tests with AWS-LC	0s
Windows MSI${{ '' }}	0s
Windows ${{ ((fromJSON(matrix.free-threading) && '(free-threading)') \|\| '') }}	0s
WASI	0s
iOS	0s
Hypothesis tests on Ubuntu	0s
Ubuntu ${{ ((fromJSON(matrix.free-threading) && '(free-threading)') \|\| '') }} ${{ ((fromJSON(matrix.bolt) && '(bolt)') \|\| '') }}	0s
Docs / Docs	1m 49s
Check if Autoconf files are up to date	0s
Docs / Doctest	5m 53s
Check if generated files are up to date	0s
Ubuntu SSL tests with OpenSSL	0s
Docs / Check EPUB	2m 7s
macOS ${{ ((fromJSON(matrix.free-threading) && '(free-threading)') \|\| '') }}	0s
Android (${{ matrix.arch }})	0s
CIFuzz	0s
Cross build Linux	0s
Address sanitizer	0s
Sanitizers${{ '' }}	0s
All required checks pass	4s
	10m 6s

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