Inline nested visitor classes into getVisitor()

[timtebeek]

• Result of running the new InlineNestedVisitorClass recipe, which replaces a getVisitor() that returns a named private static nested visitor with that visitor declared anonymously in place.

Touches NeedBraces, ExplicitLambdaArgumentTypes and RemoveToStringCallsFromArrayInstances; beyond the class declaration itself the diff is a pure re-indent, and ./gradlew build passes.

Three other recipes here match the same shape but are intentionally left alone, since their nested visitors declare private static final matchers that an anonymous class cannot hold on our Java 8 baseline.