Add comment for other annotation processors for the installation

A lot of users are having problems, because they don't quite understand the maven compiler annotationProcessorPaths. @alexis-puska suggested that we extend the installation instructions with something like:

<configuration>
    <source>1.6</source> <!-- or higher, depending on your project -->
    <target>1.6</target> <!-- or higher, depending on your project -->
    <annotationProcessorPaths>
        <path>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct-processor</artifactId>
            <version>${org.mapstruct.version}</version>
        </path>
        <!-- If you use other annotations processor add them here -->
    </annotationProcessorPaths>
</configuration>

I think that this is a good suggestion and would help other developers in issues when MapStruct and Lombok are not working well together due to wrong setup

Commencez par la page d’installation liée dans l’issue et examinez sa configuration du compilateur Maven. La tâche est terminée lorsque les instructions d’installation expliquent annotationProcessorPaths pour les processeurs d’annotations supplémentaires et incluent l’exemple de configuration proposé, tout en couvrant le contexte de configuration de MapStruct/Lombok.