Use fixit to convert function call in assertion macro

[swift-student]

We can add a deprecated macro that takes a function call like #assertWasCalled(foo(paramOne: "Hello World")) and turns it into a reference to the function and the expected input like #assertWasCalled(foo(paramOne:), with: "Hello World"). We could technically support the former, but it is unclear that by passing the function call syntax into the macro, the function would not actually be called. So utilizing a DiagnosticMessage with a fixit will allow for typing the call in a way that feels natural, while maintaining clarity that we are asserting a function was called with a certain input and not actually calling it in the process of making that assertion.