pom dependency update hint could also check annotation processors

[mbien]

java/maven.hints

• this will show dep update hints for annotation processors declared in plugin/configuration/annotationProcessorPaths/*
• had to update the implementation slightly since the list items didn't implement VersionablePOMComponent
• auto completion is not implemented for this path

java/maven.model

• removed duplicated friend declaration

example:

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.13.0</version>
        <configuration>
            <compilerArgs>
                <arg>-Xlint</arg>
            </compilerArgs>
            <annotationProcessorPaths>
                <path>
                    <groupId>org.hibernate.orm</groupId>
                    <artifactId>hibernate-jpamodelgen</artifactId>
                    <version>6.6.0.Final</version>  <!--  hint should appear if a newer version is known -->
                </path>
            </annotationProcessorPaths>
        </configuration>
    </plugin>

[matthiasblaesing]

Looks sane to me. Thank you.