minor: fix links to oracle (based on linkcheck plugin validation)
minor: fix links to oracle (based on linkcheck plugin validation)

rnveach/checkstyle,checkstyle/checkstyle,romani/checkstyle,checkstyle/checkstyle,romani/checkstyle,romani/checkstyle,rnveach/checkstyle,checkstyle/checkstyle,checkstyle/checkstyle,rnveach/checkstyle,rnveach/checkstyle,rnveach/checkstyle,checkstyle/checkstyle,romani/checkstyle,romani/checkstyle,checkstyle/checkstyle,romani/checkstyle,rnveach/checkstyle