plugin/dns64: update readme and owners (#3848)

* plugin/dns64: update readme and owners

Make @superq code owner of the plugins. Update the readme a bit:

* don't make it start with a quote
* make it look more like other README's in syntax description
* make a full corefile examples and tests these by setting the corefile
  language tag

Signed-off-by: Miek Gieben <miek@miek.nl>

* Update plugin/dns64/README.md

Co-Authored-By: Ben Kochie <superq@gmail.com>

* Update plugin/dns64/README.md

Co-Authored-By: Ben Kochie <superq@gmail.com>

* Update plugin/dns64/README.md

Co-Authored-By: Ben Kochie <superq@gmail.com>

* Update plugin/dns64/README.md

Co-Authored-By: Ben Kochie <superq@gmail.com>

* Update plugin/dns64/README.md

Co-Authored-By: Ben Kochie <superq@gmail.com>

Co-authored-by: Ben Kochie <superq@gmail.com>

CODEOWNERS

@@ -21,6 +21,7 @@ go.mod                  @miekg @chrisohaver @johnbelamaric @yongtang @stp-ip
 /plugin/cancel/         @miekg
 /plugin/chaos/          @miekg @zouyee
 /plugin/clouddns/       @miekg @yongtang
+/plugin/dns64           @superq
 /plugin/dnssec/         @isolus @miekg
 /plugin/dnstap/         @varyoo @yongtang
 /plugin/erratic/        @miekg

plugin/dns64/README.md

@@ -6,55 +6,70 @@
 
 ## Description
 
-> DNS64 describes a DNS server that when asked for a domain's AAAA records, but only finds
+The *dns64* plugin will when asked for a domain's AAAA records, but only finds A records,
-> A records, synthesizes the AAAA records from the A records.
+synthesizes the AAAA records from the A records.
 
-The synthesis in only performed if the query came in via IPv6.
+The synthesis is *only* performed **if the query came in via IPv6**.
 
 This translation is for IPv6-only networks that have [NAT64](https://en.wikipedia.org/wiki/NAT64).
 
-See [RFC 6147](https://tools.ietf.org/html/rfc6147) for more information.
-
 ## Syntax
 
+~~~
+dns64 [PREFIX]
+~~~
+
+* **PREFIX** defines a custom prefix instead of the default `64:ff9b::/96`.
+
+Or use this slightly longer form with more options:
+
 ~~~
 dns64 [PREFIX] {
-  [translate_all]
+    [translate_all]
+    prefix PREFIX
 }
 ~~~
 
-* [PREFIX] defines a custom prefix instead of the default `64:ff9b::/96`.
+* `prefix` specifies any local IPv6 prefix to use, instead of the well known prefix (64:ff9b::/96)
-* `translate_all` translates all queries, including respones that have AAAA results.
+* `translate_all` translates all queries, including responses that have AAAA results.
 
 ## Examples
 
-Translate with the default well known prefix. Applies to all queries.
+Translate with the default well known prefix. Applies to all queries (if they came in over IPv6).
 
 ~~~
-dns64
+. {
+    dns64
+}
 ~~~
 
 Use a custom prefix.
 
-~~~
+~~~ corefile
-dns64 64:1337::/96
+. {
-# Or
+    dns64 64:1337::/96
-dns64 {
+}
-    prefix 64:1337::/96
+~~~~
+
+Or
+~~~ corefile
+. {
+    dns64 {
+        prefix 64:1337::/96
+    }
 }
 ~~~
 
 Enable translation even if an existing AAAA record is present.
 
-~~~
+~~~ corefile
-dns64 {
+. {
-    translate_all
+    dns64 {
+        translate_all
+    }
 }
 ~~~
 
-* `prefix` specifies any local IPv6 prefix to use, instead of the well known prefix (64:ff9b::/96)
-
-
 ## Metrics
 
 If monitoring is enabled (via the _prometheus_ plugin) then the following metrics are exported:
@@ -71,3 +86,7 @@ Not all features required by DNS64 are implemented, only basic AAAA synthesis.
 * Resolve PTR records
 * Follow CNAME records
 * Make resolver DNSSEC aware. See: [RFC 6147 Section 3](https://tools.ietf.org/html/rfc6147#section-3)
+
+## Also See
+
+See [RFC 6147](https://tools.ietf.org/html/rfc6147) for more information on the DNS64 mechanism.