MINOR: [Docs][C++] Fix a typo

[kylebarron]

No description provided.

[github-actions]

Thanks for opening a pull request!

If this is not a minor PR. Could you open an issue for this pull request on GitHub? https://github.com/apache/arrow/issues/new/choose

Opening GitHub issues ahead of time contributes to the Openness of the Apache Arrow project.

Then could you also rename the pull request title in the following format?

GH-${GITHUB_ISSUE_ID}: [${COMPONENT}] ${SUMMARY}

or

MINOR: [${COMPONENT}] ${SUMMARY}

In the case of old issues on JIRA the title also supports:

ARROW-${JIRA_ISSUE_ID}: [${COMPONENT}] ${SUMMARY}
PARQUET-${JIRA_ISSUE_ID}: [${COMPONENT}] ${SUMMARY}

See also:

• Other pull requests
• Contribution Guidelines - How to contribute patches

[kou]

+1

Good catch!

[ursabot]

Benchmark runs are scheduled for baseline = f182a39 and contender = d10bc18. d10bc18 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Finished ⬇️0.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Finished ⬇️1.95% ⬆️1.29%] test-mac-arm
[Finished ⬇️0.26% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.37% ⬆️1.0%] ursa-thinkcentre-m75q
Buildkite builds:
[Finished] d10bc18b ec2-t3-xlarge-us-east-2
[Finished] d10bc18b test-mac-arm
[Finished] d10bc18b ursa-i9-9960x
[Finished] d10bc18b ursa-thinkcentre-m75q
[Finished] f182a39e ec2-t3-xlarge-us-east-2
[Finished] f182a39e test-mac-arm
[Finished] f182a39e ursa-i9-9960x
[Finished] f182a39e ursa-thinkcentre-m75q
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python, R. Runs only benchmarks with cloud = True
test-mac-arm: Supported benchmark langs: C++, Python, R
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java