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/mangareader.py

@@ -39,7 +39,7 @@ class MangareaderChapterExtractor(MangareaderBase, ChapterExtractor):
     test = (("https://www.mangareader.net"
              "/karate-shoukoushi-kohinata-minoru/11"), {
         "url": "061cc92a07edf17bb991ce0821fa4c77a147a860",
-        "keyword": "2893cfcd1916859fb498f3345f1929f868fe667f",
+        "keyword": "133e3e2f7c0529a35bbb16149e34c40546f8dfd6",
     })
 
     def __init__(self, match):