Rename parameter to avoid name clashing

If a class has an `actual` field/property, it clashes with the generated assertion `actual` parameter.

In this example, the `actual` parameter clashes with actual object under test in `actual.getActual();`
```java
public S hasActual(boolean actual) {
// check that actual Group we want to make assertions on is not null.
isNotNull();

// overrides the default error message with a more explicit one
String assertjErrorMessage = "\nExpecting actual of:\n <%s>\nto be:\n <%s>\nbut was:\n <%s>";

// check
boolean actualActual = actual.getActual();
if (actualActual != actual) {
failWithMessage(assertjErrorMessage, actual, actual, actualActual);
}

// return the current assertion for method chaining
return myself;
}

```