Merge pull request bitcoin#1074 from sanket1729/patch-1

Change `witness` to signature

Author: luke-jr

bip-0118.mediawiki

@@ -92,7 +92,7 @@ Any participant can take a transaction and rewrite it by changing the
 hash reference to the previous output, without invalidating the
 signatures.
 This allows transactions to be bound to any output that matches the
-value committed to in the <tt>witness</tt> and whose <tt>witnessProgram</tt>,
+value committed to in the signature and whose <tt>witnessProgram</tt>,
 combined with the spending transaction's <tt>witness</tt> returns <tt>true</tt>.
 
 Previously, all information in the transaction was committed in the