fix repeated content address example
fix repeated content address example

Signed-off-by: xiekeyang <43239a1d761bfde9c48de11b7981f737d518cda0@huawei.com>

vbatts/oci-image-spec,jonboulle/image-spec,mattspencer-arm/image-spec,mattspencer-arm/image-spec,opencontainers/image-spec,vbatts/oci-image-spec,opencontainers/image-spec,jonboulle/image-spec