Merge pull request bitcoin#647 from dangershony/patch-5

Fix a grammar error

Author: luke-jr

bip-0098.mediawiki

@@ -131,7 +131,7 @@ There are eight possible configurations of internal nodes, as given in the follo
 
 :: [[File:bip-0098/node-variants.png]]
 
-In this diagram, DESCEND means the branch links to another internal node, as indicated by the its child graph elements labeled "...";
+In this diagram, DESCEND means the branch links to another internal node, as indicated by its child graph elements labeled "...";
 SKIP means the branch contains a hash of an elided subtree or element, and the fast-SHA256 root hash of this subtree or double-SHA256 hash of the element is included in the proof structure; and
 VERIFY means the branch contains an externally provided hash that is needed as witness for the verification of the proof.
 In tabular form, these code values are: