Fix typo in BIP 125

Author: jamesob

bip-0125.mediawiki

@@ -85,7 +85,7 @@ unconfirmed.
 
 Wallets that don't want to signal replaceability should use either a max
 sequence number (0xffffffff) or a sequence number of (0xffffffff-1) when
-then also want to use locktime; all known wallets currently do this.
+they also want to use locktime; all known wallets currently do this.
 They should also take care not to spend any unconfirmed transaction that
 signals replaceability explicitly or through inherited signaling; most wallets also
 currently do this by not spending any unconfirmed transactions except