Modify the cache.php docblocks (laravel#5468)

In new versions of laravel we do not directly specify the "cache driver" anymore but rather a "cache store", so it does not make sense to mention the drivers up there since laravel supports any arbitrary values defined below it by the user.

config/cache.php

@@ -13,9 +13,6 @@
     | using this caching library. This connection is used when another is
     | not explicitly specified when executing a given caching function.
     |
-    | Supported: "apc", "array", "database", "file",
-    |            "memcached", "redis", "dynamodb"
-    |
     */
 
     'default' => env('CACHE_DRIVER', 'file'),
@@ -29,6 +26,9 @@
     | well as their drivers. You may even define multiple stores for the
     | same cache driver to group types of items stored in your caches.
     |
+    | Supported drivers: "apc", "array", "database", "file",
+    |            "memcached", "redis", "dynamodb"
+    |
     */
 
     'stores' => [