RecursiveToStringStyle does not handle nested Maps correctly

When using RecursiveToStringStyle to include all member fields of all nested objects, it works for simple Maps, but as soon as I have Maps as values inside another Map, the contents is not included any more, but only a Object.toString() seems to be appended for the objects instead.

A possible fix would be to add the following to RecursiveToStringStyle, although there might be a better way to fix this:

        @Override
        protected void appendDetail(StringBuffer buffer, String fieldName, Map<?, ?> map) {
            appendClassName(buffer, map);
            appendIdentityHashCode(buffer, map);
            appendDetail(buffer, fieldName, map.entrySet());
        }

See the attached unit-test for a reproducer.

Please also note that RecursiveToStringStyleTest in commons-lang seems to mostly work on the DefaultStyle instead, see https://github.com/apache/commons-lang/blob/master/src/test/java/org/apache/commons/lang3/builder/RecursiveToStringStyleTest.java#L38, only one method, testPerson(), seems to actually do a real test here!