onm.Address.visitChildAddresses

[ChrisRus]

Add note that indicates that the visitation is scoped to a single rank; the set of immediate descendant namespaces of the called onm.Address object instance are visited. Also, clarify that the set of visited addresses is not filtered as a function of the value of 'namespaceType' (i.e. currently both 'child' and 'extensionPoint' namespace addresses are visited).