[sxypix] add support (#4507 #8391 #8574)

* Add support for sxypix.com
* update & simplify
    - text.extract -> text.extr
    - self.request().json() -> self.request_json()
    - use self.groups
    - remove __init__
    - list comprehension
* update test results

---------

Co-authored-by: Mike Fährmann <mike_faehrmann@web.de>

test/results/sxypix.py

@@ -0,0 +1,25 @@
+# -*- coding: utf-8 -*-
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+
+from gallery_dl.extractor import sxypix
+
+
+__tests__ = (
+{
+    "#url"     : "https://sxypix.com/w/c42ec529474789f812dd8ba26103855f",
+    "#category": ("", "sxypix", "gallery"),
+    "#class"   : sxypix.SxypixGalleryExtractor,
+    "#count"   : 35,
+
+    "count"     : 35,
+    "num"       : range(1, 35),
+    "filename"  : "hash:md5",
+    "extension" : "webp",
+    "gallery_id": "c42ec529474789f812dd8ba26103855f",
+    "title"     : "#MommysBoy - Penny Barber - Coddling Her Boy",
+},
+
+)