Add link to implementation

Also change the phrasing to more clearly indicate when block-relay-only peering
was deployed.

Author: sdaftuar

bip-disable-tx.mediawiki

@@ -19,7 +19,7 @@ block-relay-only connections that are currently in use on the network.
 
 ==Motivation==
 
-For nearly the past year, software has been deployed[1] which initiates
+Since 2019, software has been deployed[1] which initiates
 connections on the Bitcoin network and sets the transaction relay field
 (introduced by BIP 37 and also defined in BIP 60) to false, to prevent
 transaction relay from occurring on the connection. Additionally, addr messages
@@ -88,7 +88,7 @@ message, subject to the feature negotiation of BIP 152.
 
 ==Implementation==
 
-TBD
+https://github.com/bitcoin/bitcoin/pull/20726
 
 ==References==