updated messgae

Author: venom1204

NEWS.md

@@ -10,16 +10,17 @@
 
 ### NEW FEATURES
 
-1. New `sort_by()` method for data.tables, [#6662](https://github.com/Rdatatable/data.table/issues/6662). It uses `forder()` to improve upon the data.frame method and also match `DT[order(...)]` behavior with respect to locale, and allows sorting by expressions or functions. Thanks @rikivillalba for the suggestion and PR.
+1. New `sort_by()` method for data.tables, [#6662](https://github.com/Rdatatable/data.table/issues/6662). It uses `forder()` to improve upon the data.frame method and also match `DT[order(...)]` behavior with respect to locale. Thanks @rikivillalba for the suggestion and PR.
+
 
 ```r
     DT = data.table(a = c(1, 2, 1), b = c(3, 1, 2))
-    # sort by column 'b'
-    sort_by(DT, ~b)
+    # sort by 'a', then 'b'
+    sort_by(DT, ~a + b)
     #    a b
-    # 1: 2 1
-    # 2: 1 2
-    # 3: 1 3
+    # 1: 1 2
+    # 2: 1 3
+    # 3: 2 1
 ```
 
 2. `melt()` now supports using `patterns()` with `id.vars`, [#6867](https://github.com/Rdatatable/data.table/issues/6867). Thanks to Toby Dylan Hocking for the suggestion and PR.