Align format for section headers in the documentation

[dnskr]

Description

Align format for section headers in the documentation to follow the same style.

Motivation and Context

Minor change just to keep formatting style consistent across documentation.

Impact

None

Test Plan

Build the documentation locally, ensure it looks the same

Contributor checklist

• Please make sure your submission complies with our contributing guide, in particular code style and commit standards.
• PR description addresses the issue accurately and concisely. If the change is non-trivial, a GitHub Issue is referenced.
• Documented new properties (with its default value), SQL syntax, functions, or other functionality.
• If release notes are required, they follow the release notes guidelines.
• Adequate tests were added if applicable.
• CI passed.

Release Notes

== NO RELEASE NOTE ==

[steveburnett]

Thanks for all this!

[steveburnett]

LGTM! (docs)

Pull updated branch, new local doc build, looks good. Thanks!