Typo in comment in nbtree.h

Hi

Following along with a btree bug report, I saw a typo "referencd" in a
comment. Also "we've" seems a bit odd here, but maybe it's just me.
Maybe it should be like this?

--- a/src/include/access/nbtree.h
+++ b/src/include/access/nbtree.h
@@ -522,7 +522,7 @@ typedef struct BTScanPosData
Buffer buf; /* if valid, the
buffer is pinned */

XLogRecPtr lsn; /* pos in the WAL
stream when page was read */
- BlockNumber currPage; /* page we've referencd by
items array */
+ BlockNumber currPage; /* page referenced by items array */
BlockNumber nextPage; /* page's right link when we
scanned it */

/*

--
Thomas Munro
http://www.enterprisedb.com