Add hint to Falsy Bouncer challenge description

Updates the Falsy Bouncer challenge description to include a hint
to help campers understand how they should approach the challenge
without revealing too much information or locking the camper into
a particular solution.

seed/challenges/02-javascript-algorithms-and-data-structures/basic-algorithm-scripting.json

@@ -685,6 +685,7 @@
       "description": [
         "Remove all falsy values from an array.",
         "Falsy values in JavaScript are <code>false</code>, <code>null</code>, <code>0</code>, <code>\"\"</code>, <code>undefined</code>, and <code>NaN</code>.",
+        "Hint: Try converting each value to a Boolean.",
         "Remember to use <a href=\"http://forum.freecodecamp.com/t/how-to-get-help-when-you-are-stuck/19514\" target=\"_blank\">Read-Search-Ask</a> if you get stuck. Write your own code."
       ],
       "challengeSeed": [