Replaced underscores with hypens in D2 config in remaining files:

    doc/examples/ddns/sample1.json
    doc/examples/ddns/template.json
    doc/guide/ddns.xml
    src/bin/d2/tests/d2_process_tests.sh.in
    src/bin/keactrl/kea.conf.pre
    src/bin/keactrl/tests/keactrl_tests.sh.in