Fix typo

Author: OrfeasLitos

bip-0143.mediawiki

@@ -114,7 +114,7 @@ Refer to the reference implementation, reproduced below, for the precise algorit
   ss << hashSequence;
   // The input being signed (replacing the scriptSig with scriptCode + amount)
   // The prevout may already be contained in hashPrevout, and the nSequence
-  // may already be contain in hashSequence.
+  // may already be contained in hashSequence.
   ss << txTo.vin[nIn].prevout;
   ss << static_cast<const CScriptBase&>(scriptCode);
   ss << amount;