Only copy questions when creating reply

In particular, there may be additional records which should not be copied

PUBLISHED_FROM=6b348868cb62d7b3fc4df0e935ffd5a31a314a08

docs/c-api/dns.h/items.json

@@ -18,7 +18,7 @@
         },
         {
             "type": "markdown",
-            "name": "mg_dns_copy_body.md"
+            "name": "mg_dns_copy_questions.md"
         },
         {
             "type": "markdown",

docs/c-api/dns.h/mg_dns_copy_body.md

@@ -1,15 +0,0 @@
----
-title: "mg_dns_copy_body()"
-decl_name: "mg_dns_copy_body"
-symbol_kind: "func"
-signature: |
-  int mg_dns_copy_body(struct mbuf *io, struct mg_dns_message *msg);
----
-
-Append already encoded body from an existing message.
-
-This is useful when generating a DNS reply message which includes
-all question records.
-
-Return number of appened bytes. 
-

docs/c-api/dns.h/mg_dns_copy_questions.md

@@ -0,0 +1,15 @@
+---
+title: "mg_dns_copy_questions()"
+decl_name: "mg_dns_copy_questions"
+symbol_kind: "func"
+signature: |
+  int mg_dns_copy_questions(struct mbuf *io, struct mg_dns_message *msg);
+---
+
+Append already encoded questions from an existing message.
+
+This is useful when generating a DNS reply message which includes
+all question records.
+
+Return number of appened bytes. 
+