Fixed broken link

The URL seems to have changed - the Pile doesn't work as is, with mystic.the-eye.eu, but works file with the-eye.eu

the_pile.py

@@ -50,7 +50,7 @@ _LICENSES = {
     "uspto": "Unknown",
 }
 
-_HOST_URL = "https://mystic.the-eye.eu"  # Before: "https://the-eye.eu"
+_HOST_URL = "https://the-eye.eu"  # Before: "https://the-eye.eu"
 _DATA_URLS = {
     "all": {
         "train": [f"{_HOST_URL}/public/AI/pile/train/{i:0>2}.jsonl.zst" for i in range(30)],