Sounds.json's attenuation distance doesn't work with type: event

Attenuation distance controls how far away a sound can be heard before it's silent. This works properly with type "sound" (default) entries, but not with type "event" entries; it'll use the parent's attenuation distance, rather than using the event's, or multiplying with it (divided by 16).

Steps to reproduce:

1. Create a sounds.json with the following:

   {
       "custom.parent": {
           "sounds": [
               {
                   "name": "mob/zombie/hurt2"
               }
           ]
       },
       "custom.event": {
           "sounds": [
               {
                   "type": "event",
                   "name": "custom.parent",
                   "attenuation_distance": 2
               }
           ]
       },
       "custom.sound": {
           "sounds": [
               {
                   "name": "mob/zombie/hurt2",
                   "attenuation_distance": 2
               }
           ]
       }
   }

2. Logic dictates that custom.sound and custom.event both have an attenuation distance of 2 blocks.
3. Use /playsound custom.sound master @s ~ ~ ~ and /playsound custom.sound master @s ~ ~ ~3
4. Observe how the first command's sound can be heard, but the second one can't
5. Use /playsound custom.event master @s ~ ~ ~ and /playsound custom.event master @s ~ ~ ~3
6. Observe how the both command's sound can be heard.

Expected result:
custom.event has an attenuation distance of 2 blocks.

Actual result:
custom.event has an attenuation distance of the default value of 16 blocks because that's what custom.parent's attenuation distance is.