[urlshortener] add tinyurl.com as an example

docs/gallery-dl-example.conf

@@ -317,6 +317,10 @@
             "archive": "~/gallery-dl/custom-archive-file-for-TBIB.db",
             "filename": "{id}_{md5}.{extension}",
             "sleep-request": [0, 1.2]
+        },
+
+        "urlshortener": {
+            "tinyurl": {"root": "https://tinyurl.com"}
         }
     },
 

gallery_dl/extractor/urlshortener.py

@@ -11,7 +11,7 @@ from .. import exception
 
 
 class UrlshortenerExtractor(BaseExtractor):
-    """Base class for general-purpose URL shorteners"""
+    """Extractor for general-purpose URL shorteners"""
     basecategory = "urlshortener"
     test = (
         ("https://bit.ly/3cWIUgq", {