Merge pull request bitcoin#125 from fjahr/patch-1

Link design section of BIP Schnorr in Specification

Author: sipa

bip-taproot.mediawiki

@@ -50,7 +50,7 @@ Not included in this proposal are additional features like new sighash modes or
 
 This section specifies the Taproot consensus rules. Validity is defined by exclusion: a block or transaction is valid if no condition exists that marks it failed.
 
-The notation below follows that of bip-schnorr. This includes the ''hash<sub>tag</sub>(x)'' notation to refer to ''SHA256(SHA256(tag) || SHA256(tag) || x)''. To the best of the authors' knowledge, no existing use of SHA256 in Bitcoin feeds it a message that starts with two single SHA256 outputs, making collisions between ''hash<sub>tag</sub>'' with other hashes extremely unlikely.
+The notation below follows that of [https://github.com/sipa/bips/blob/bip-schnorr/bip-schnorr.mediawiki#design bip-schnorr]. This includes the ''hash<sub>tag</sub>(x)'' notation to refer to ''SHA256(SHA256(tag) || SHA256(tag) || x)''. To the best of the authors' knowledge, no existing use of SHA256 in Bitcoin feeds it a message that starts with two single SHA256 outputs, making collisions between ''hash<sub>tag</sub>'' with other hashes extremely unlikely.
 
 === Script validation rules ===