Fix capitalization of H2 headers

[sdwheeler]

Fix capitalization of H2 headers

• Fixes AB#453965

[learn-build-service-prod]

Learn Build status updates of commit 5aad650:

❌ Validation status: errors

Please follow instructions here which may help to resolve issue.

File	Status	Preview URL	Details
	❌Error		Details

• Line 0, Column 0: [Error: PSMD2Yaml_FileLoadFailed] Failed to load file: C:/LocalRun/W/fgai-s/module/mapping/monikerMapping.json. PackageRoot, ReferenceTocUrl, and ConceptualTocUrl are required for every moniker. PackageRoot should be a valid relative path to docset root.

For more details, please refer to the build report.

Note: Your PR may contain errors or warnings or suggestions unrelated to the files you changed. This happens when external dependencies like GitHub alias, Microsoft alias, cross repo links are updated. Please use these instructions to resolve them.