DNS resolver documentation updated

Author: rashik-bhasin

website/docs/r/dns_resolver.html.markdown

@@ -13,6 +13,7 @@ This resource provides the Resolver resource in Oracle Cloud Infrastructure Dns
 Updates the specified resolver with your new information.
 
 Note: Resolvers are associated with VCNs and created when a VCN is created. Wait until created VCN's state shows as Available in OCI console before updating DNS resolver properties.
+Also a VCN cannot be deleted while its resolver has resolver endpoints. Additionally a resolver endpoint cannot be deleted if it is referenced in the resolver's rules. To remove the rules from a resolver user needs to update the resolver resource. Since DNS Resolver gets deleted when VCN is deleted there is no support for Delete for DNS Resolver.
 
 ## Example Usage