refer to RFC 2136 explicitly in the text, and capitalize Secure DNS UPDATE

draft-dkg-dprive-demux-dns-http.md

@@ -347,9 +347,10 @@ Recursion Desired) is set when a packet is sent from a stub to a
 recursive resolver.  The value of such an octet is 0x01.  This value
 never occurs in octet 4 of a legitimate HTTP client.
 
-But under DNS UPDATE, Opcode is set to 5 and all the option bits are
-cleared, which means this value would have 0x40 (ASCII '@'), which
-could legitimately occur in some HTTP requests at this position..
+But under DNS UPDATE ({{RFC2136}}, Opcode is set to 5 and all the
+option bits are cleared, which means this value would have 0x40 (ASCII
+'@'), which could legitimately occur in some HTTP requests at this
+position..
 
 octet 5
 -------
@@ -405,7 +406,7 @@ octets 12 and 13
 
 In streaming DNS, octets 12 and 13 represent the number of Additional
 RRs.  When a DNS query is sent with EDNS(0), the OPT RR is accounted
-for here.  So this is often either 0x0000 or 0x0001.  In a secure DNS
+for here.  So this is often either 0x0000 or 0x0001.  In a Secure DNS
 UPDATE {{RFC3007}}, the SIG(0) or TSIG record is also found in this
 section, which could increase the values of these octets to 0x0002.
 No HTTP client will send octets with these low values at these