Merge bitcoin#1044: BIP155: Remove external link

cd1f225 BIP 155: Remove bitcoin.org link. (kiminuo)

Pull request description:

  Fix link.

ACKs for top commit:
  laanwj:
    Thanks you, ACK cd1f225

Tree-SHA512: f798246ddffc2564385a2e071da02e47457ced15e502a8b500a10c2a4f5134cea750042e916bbfac39966e85efd554ad333a908be602a4cfcf09fa058840a527

Author: laanwj

bip-0155.mediawiki

@@ -44,8 +44,7 @@ interpreted as described in RFC 2119<ref>[https://tools.ietf.org/html/rfc2119 RF
 
 The <code>addrv2</code> message is defined as a message where <code>pchCommand == "addrv2"</code>.
 It is serialized in the standard encoding for P2P messages.
-Its format is similar to the current <code>addr</code> message format
-<ref>[https://bitcoin.org/en/developer-reference#addr Bitcoin Developer Reference: addr message]</ref>, with the difference that the 
+Its format is similar to the current <code>addr</code> message format, with the difference that the 
 fixed 16-byte IP address is replaced by a network ID and a variable-length address, and the services format has been changed to [https://en.bitcoin.it/wiki/Protocol_documentation#Variable_length_integer CompactSize].
 
 This means that the message contains a serialized <code>std::vector</code> of the following structure: