doc: fix indentation of config example
doc: fix indentation of config example

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