[scala] Fix javadoc generation and upload

Due to the different project structure, the paths need
to be adjusted

pmd-scala-modules/pmd-scala-common/pom.xml

@@ -73,6 +73,28 @@
                         </execution>
                     </executions>
                 </plugin>
+
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-javadoc-plugin</artifactId>
+                    <configuration>
+                        <offlineLinks>
+                            <offlineLink>
+                                <location>${project.basedir}/../../pmd-lang-test/target/dokka/pmd-lang-test</location>
+                                <url>../../pmd-lang-test/${project.version}</url>
+                            </offlineLink>
+                            <offlineLink>
+                                <location>${project.basedir}/../../pmd-test/target/apidocs</location>
+                                <url>../../pmd-test/${project.version}</url>
+                            </offlineLink>
+                            <!-- core needs to be last, because the package "net.sourceforge.pmd.lang" is both in pmd-core and pmd-test -->
+                            <offlineLink>
+                                <location>${project.basedir}/../../pmd-core/target/apidocs</location>
+                                <url>../../pmd-core/${project.version}</url>
+                            </offlineLink>
+                        </offlineLinks>
+                    </configuration>
+                </plugin>
             </plugins>
         </pluginManagement>
     </build>