Define the behavior of AvoidAsyncSuffix for Event-based Asynchronous Pattern

[sharwell]

The current implementation of the AvoidAsyncSuffix analyzer only targets the Task-based Asynchronous Pattern (TAP). The Event-based Asynchronous Pattern (EAP) also uses the Async suffix for certain methods, but the signatures are different from the TAP.

The behavior of the AvoidAsyncSuffix analyzer should be fully defined for this case, and tests included to detect regressions.