add diff statement to the Audit-2.0 feature page

[dmuelle]

For OpenLiberty/open-liberty#27475

add the following extended description to the autogenerated audit-2.0 feature page:

The Audit 2.0 feature provides the same audit records as the Audit 1.0 feature (audit-1.0) but it does not generate records for REST Handler applications. If you need to keep audit records for REST Handler applications, use the Audit 1.0 feature.