Plugin incorrectly gives umapped target warning for Immutables-classes

[sleicht]

From the immutables generated classes have the builder method 'from(...)' which creates a new copy of an instance as builder instance. The mapstruct processor correctly handles those methods in the ImmutablesAccessorNamingStrategy. The IntelliJ plugin, on the other hand, does add those methods as missing property into the problem list: Unmapped target property: from.