src/types.c: Clarify comment for addr_submit (style)

[adns] / regress / case-noinfto.out

adns debug: using nameserver 172.18.45.36
a.b.c.d flags 0 type 1 A(-) submitted
a.b.c.d flags 0 type A(-): DNS query timed out; nrrs=0; cname=$; owner=$; ttl=604744
rc=0