remove '&' from URL patterns

'/?&#' -> '/?#' and '?&#' -> '?#'

According to https://www.ietf.org/rfc/rfc3986.txt, URLs are
"organized hierarchically" by using "the slash ("/"), question
mark ("?"), and number sign ("#") characters to delimit components"

gallery_dl/extractor/behance.py

@@ -151,7 +151,7 @@ class BehanceUserExtractor(BehanceExtractor):
     """Extractor for a user's galleries from www.behance.net"""
     subcategory = "user"
     categorytransfer = True
-    pattern = r"(?:https?://)?(?:www\.)?behance\.net/([^/?&#]+)/?$"
+    pattern = r"(?:https?://)?(?:www\.)?behance\.net/([^/?#]+)/?$"
     test = ("https://www.behance.net/alexstrohl", {
         "count": ">= 8",
         "pattern": BehanceGalleryExtractor.pattern,