expand description, response to @SleeplessByte suggestion

Author: bencoman

exercises/etl/canonical-data.json

@@ -10,9 +10,9 @@
         "such that keys are integers. e.g. in JavaScript, it might look ",
         "like `transform( { 1: ['A'] } );`"
       ],
-      "description": "Transform",
-      "comments": [ "Transforms the a set of scrabble data previously indexed by the tile score",
-                    "to a set of data indexed by the tile letter"
+      "description": "Transform legacy to new",
+      "comments": [ "Transforms a set of legacy scrabble data stored as letters per score",
+                    "to a set of data stored score per letter"
       ],
       "cases": [
         {