Merge pull request bitcoin#448 from isghe/bip23_fix_link

minor: fix link to BIP 22

Author: luke-jr

bip-0023.mediawiki

@@ -13,7 +13,7 @@ This BIP describes extensions to the getblocktemplate JSON-RPC call to enhance p
 
 ==Specification==
 
-Note that all sections of this specification are optional extensions on top of [[BIP 0022|BIP 22]].
+Note that all sections of this specification are optional extensions on top of [[bip-0022.mediawiki|BIP 22]].
 
 ===Summary Support Levels===