Fix for issue #981

Author: tsantalis

src/main/java/org/refactoringminer/astDiff/matchers/wrappers/FieldDeclarationMatcher.java

@@ -81,6 +81,8 @@ private void processFieldDeclaration(Tree srcTree, Tree dstTree, UMLAttribute sr
             if (srcUMLAttribute instanceof UMLEnumConstant && dstUMLAttribute instanceof UMLEnumConstant) {
                 //JavaDocs are mapped as well.
                 new LeafMatcher().match(srcAttr,dstAttr,mappingStore);
+                new JavaDocMatcher(optimizationData, srcUMLAttribute.getJavadoc(), dstUMLAttribute.getJavadoc(), umlJavadocDiff)
+                .match(srcTree, dstTree, mappingStore);
                 return;
             }
         }