Update bonfire challenge description

Clarified the description on the Return Largest Numbers in Arrays challenge.

seed_data/bonfires.json

@@ -110,7 +110,7 @@
     "name": "Return Largest Numbers in Arrays",
     "difficulty": "1.06",
     "description": [
-      "Return an array consisting of the largest numbers in the provided array. The array will contain 4 sub-arrays.",
+      "Return an array consisting of the largest number from each provided sub-array. For simplicity, the provided array will contain exactly 4 sub-arrays.",
       "Remember, you can iterate through an array with a simple for loop, and access each member with array syntax arr[i] .",
       "If you are writing your own Chai.js tests, be sure to use a deep equal statement instead of an equal statement when comparing arrays."
     ],