BIP141: Add BIP173 to references.

Author: jonathancross

bip-0141.mediawiki

@@ -324,6 +324,7 @@ https://github.com/bitcoin/bitcoin/pull/8149
 *[[bip-0016.mediawiki|BIP16 Pay to Script Hash]]
 *[[bip-0143.mediawiki|BIP143 Transaction Signature Verification for Version 0 Witness Program]]
 *[[bip-0144.mediawiki|BIP144 Segregated Witness (Peer Services)]]
+*[[bip-0173.mediawiki|BIP173 Base32 address format for native v0-16 witness outputs]]
 
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