Extend virtual domain name description with clarification about wildc…

…ard names behaviour

Signed-off-by: Anton Kaymakchi <anton.kaymakchi@transferwise.com>

api/envoy/data/dns/v3/dns_table.proto

@@ -129,9 +129,14 @@ message DnsTable {
         "envoy.data.dns.v2alpha.DnsTable.DnsVirtualDomain";
 
     // A domain name for which Envoy will respond to query requests.
-    // Wildcard records are supported on the first label only, e.g. `*.example.com` or `*.subdomain.example.com`.
-    // Names such as `*example.com`, `subdomain.*.example.com`, `*subdomain.example.com`, etc
-    // are not valid wildcard names and asterisk will be interpreted as a literal `*` character.
+    // Wildcard records are supported on the first label only, e.g. ``*.example.com`` or ``*.subdomain.example.com``.
+    // Names such as ``*example.com``, ``subdomain.*.example.com``, ``*subdomain.example.com``, etc
+    // are not valid wildcard names and asterisk will be interpreted as a literal ``*`` character.
+    // Wildcard records match subdomains on any levels, e.g. ``*.example.com`` will match
+    // ``foo.example.com``, ``bar.foo.example.com``, ``baz.bar.foo.example.com``, etc. In case there are multiple
+    // wildcard records, the longest wildcard match will be used, e.g. if there are wildcard records for
+    // ``*.example.com`` and ``*.foo.example.com`` and the query is for ``bar.foo.example.com``, the latter will be used.
+    // Specific records will always take precedence over wildcard records.
     string name = 1 [(validate.rules).string = {min_len: 1 well_known_regex: HTTP_HEADER_NAME}];
 
     // The configuration containing the method to determine the address of this endpoint