remove errant comma

Author: kay-kim

source/reference/method/db.collection.update.txt

@@ -189,7 +189,7 @@ db.collection.update()
 
         db.products.update( { item: "magazine", qty: { $gt: 5 } }, { $set: { x: 25, y: 50 } }, { upsert: true } )
 
-     This operation, will:
+     This operation will:
 
      - update a single document in the ``products`` collection that
        matches the query criteria, setting the value of the field