Remove warnings for fluent removers.

Nobody has claimed this yet.

If [issue#3072](https://github.com/mapstruct/mapstruct/issues/3072) in mapstruct is merged the idea-plugin will give false errors for fluent remover's.

Given the Source class:

public class Source {
private List strings = new ArrayList<>();
public List getStrings() {
return strings;
}
public void setStrings(List strings) {
this.strings = strings;
}
}

and the Target class:

public class Target {
private List strings = new ArrayList<>();
public List getStrings() {
return strings;
}
public void setStrings(List strings) {
this.strings = strings;
}
public Target strings(List strings) {
this.strings.addAll( strings );
return this;
}
public Target addString(String string) {
strings.add( string );
return this;
}
public Target removeString(String string) {
strings.remove( string );
return this;
}
}

and finally this Mapper:

@Mapper
public interface MapperWithRemoverInTarget {
Target map(Source source);
}

the plugin should no longer produce any warnings nor errors.

Start by reproducing the Source, Target, and MapperWithRemoverInTarget example in the IntelliJ IDEA plugin with the MapStruct fluent-remover change from issue #3072. Trace the diagnostics that inspect the Target methods; done means the example produces no warnings or errors.

Written by the indexing model from the issue text.