This is the opposite of #178:

void FooAsync() { }

Becomes:

void Foo() { }

The async keyword is not necessary for the method to have the Async postfix. All it needs to be async is to return a Task.
When renaming the method, all references have to be renamed as well and no code should break.
Should work on interfaces as well.

Category: Style
Diagnostic Id: CC0072
Severity: Info