Update descriptions as per PR review comments

Author: bunnymatic

exercises/etl/canonical-data.json

@@ -1,9 +1,9 @@
 {
   "transform": {
-    "description": "transforms the input map from a map of value: [ keys ] to a map of key: value for each of the keys",
+    "description": "transforms the a set of scrabble data previously indexed by the tile score to a set of data indexed by the tile letter",
     "cases": [
       {
-        "description": "transforms one value",
+        "description": "transforms a single letter",
         "input": {
           "1": ["A"]
         },
@@ -12,7 +12,7 @@
         }
       },
       {
-        "description": "transforms more values",
+        "description": "transforms single score with multiple letters",
         "input": {
           "1": ["A", "E", "I", "O", "U" ]
         },
@@ -25,7 +25,7 @@
         }
       },
       {
-        "description": "transforms more keys",
+        "description": "transforms multiple scores with multiple letters",
         "input": {
           "1": ["A", "E"],
           "2": ["D", "G"]
@@ -38,7 +38,7 @@
         }
       },
       {
-        "description": "transforms a full data set",
+        "description": "transforms the full set of scrabble tiles (multiple scores with differing numbers of letters)",
         "input": {
           "1": [ "A", "E", "I", "O", "U", "L", "N", "R", "S", "T" ],
           "2": [ "D", "G" ],