[xnxx] Add `xnxx3.com` (#3188)

Authored by: rozari0

yt_dlp/extractor/xnxx.py

@@ -13,7 +13,7 @@ from ..utils import (
 
 
 class XNXXIE(InfoExtractor):
-    _VALID_URL = r'https?://(?:video|www)\.xnxx\.com/video-?(?P<id>[0-9a-z]+)/'
+    _VALID_URL = r'https?://(?:video|www)\.xnxx3?\.com/video-?(?P<id>[0-9a-z]+)/'
     _TESTS = [{
         'url': 'http://www.xnxx.com/video-55awb78/skyrim_test_video',
         'md5': '7583e96c15c0f21e9da3453d9920fbba',
@@ -32,6 +32,9 @@ class XNXXIE(InfoExtractor):
     }, {
         'url': 'http://www.xnxx.com/video-55awb78/',
         'only_matching': True,
+    }, {
+        'url': 'http://www.xnxx3.com/video-55awb78/',
+        'only_matching': True,
     }]
 
     def _real_extract(self, url):