change results of text.nameext_from_url()

Instead of getting a complete 'filename' from an URL and splitting that
into 'name' and 'extension', the new approach gets rid of the complete
version and renames 'name' to 'filename'. (Using anything other than
{extension} for a filename extension doesn't really work anyway)

Example: "https://example.org/path/filename.ext"

before:
- filename : filename.ext
- name     : filename
- extension: ext

now:
- filename : filename
- extension: ext

gallery_dl/extractor/mangapanda.py

@@ -22,7 +22,7 @@ class MangapandaChapterExtractor(MangapandaBase, MangareaderChapterExtractor):
     pattern = r"(?:https?://)?(?:www\.)?mangapanda\.com((/[^/?&#]+)/(\d+))"
     test = ("https://www.mangapanda.com/red-storm/2", {
         "url": "1f633f776e950531ba9b1e81965316458e785261",
-        "keyword": "32b5e84017c2bf5f122b339ecf40899e41f18cc9",
+        "keyword": "b24df4b9cc36383fb6a44e06d32a3884a4dcb5fb",
     })