Update attestation-structure.md

Fix H3 that should have been an H2

Author: timwarner-msft

articles/governance/policy/concepts/attestation-structure.md

@@ -19,7 +19,7 @@ Below is an example of creating a new attestation resource:
 PUT http://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.PolicyInsights/attestations/{name}?api-version=2019-10-01
 ```
 
-#### Request body
+## Request body
 
 Below is a sample attestation resource JSON object:
 
@@ -59,4 +59,4 @@ Because attestations are a separate resource from policy assignments, they have
 
 - Review [Understanding policy effects](effects.md).
 - Study the [initiative definition structure](./initiative-definition-structure.md)
-- Review examples at [Azure Policy samples](../samples/index.md).
+- Review examples at [Azure Policy samples](../samples/index.md).