transfer: small doc update (#3426)
transfer: small doc update (#3426)

Tweak the README a little. Name and spell out axfr/ixfr.

Signed-off-by: Miek Gieben <00b357f94cf3a1145a32703fb42e2d80418ab806@miek.nl>
coredns/coredns,miekg/coredns,yongtang/coredns,chrisohaver/coredns,johnbelamaric/coredns,johnbelamaric/coredns,miekg/coredns