Fix patch body schema

[mikekistler]

This PR fixes the PatchBodyParametersSchema rule to check nested properties.

Includes tests.

Some format and spelling errors corrected as well, but done in a separate commit.

Fixes Azure/azure-sdk-tools#7701

[konrad-jamrozik]

Just deployed to production:

• https://dev.azure.com/azure-sdk/internal/_releaseProgress?_a=release-environment-logs&releaseId=24441&environmentId=30096