minor: change to phrasing in javascript reference

Author: Sam Kleinman

source/reference/javascript.txt

@@ -390,7 +390,7 @@ Call cursor methods on cursors to modify how MongoDB returns objects to the curs
 
    Call this method on a query to override MongoDB's default index
    selection and query optimization process. The argument is an index
-   specification, as if to :func:`db.collection.ensureIndex()`. Use
+   specification, like the argument to :func:`ensureIndex() <db.collection.ensureIndex()>`. Use
    :func:`db.collection.getIndexes()` to return the list of current indexes on a
    collection.