update docs

- document '"mode": "jsonl"' for metadata pp
- remove 'username' and 'password' from 'instagram'
- add 'ytdl' example (#3180)

docs/configuration.rst

@@ -3592,7 +3592,9 @@ Description
     Selects how to process metadata.
 
     * ``"json"``: write metadata using `json.dump()
-      <https://docs.python.org/3/library/json.html#json.dump>`_
+      <https://docs.python.org/3/library/json.html#json.dump>`__
+    * ``"jsonl"``: write metadata in `JSON Lines
+      <https://jsonlines.org/>`__ format
     * ``"tags"``: write ``tags`` separated by newlines
     * ``"custom"``: write the result of applying `metadata.content-format`_
       to a file's metadata dictionary

docs/gallery-dl-example.conf

@@ -210,6 +210,19 @@
             "text-tweets": true
         },
 
+        "ytdl":
+        {
+            "#": "enable 'ytdl' extractor",
+            "#": "i.e. invoke ytdl on all otherwise unsupported input URLs",
+            "enabled": true,
+
+            "#": "use yt-dlp instead of youtube-dl",
+            "module": "yt_dlp",
+
+            "#": "load ytdl options from config file",
+            "config-file": "~/yt-dlp.conf"
+        },
+
         "mastodon":
         {
             "#": "add 'tabletop.social' as recognized mastodon instance",

docs/gallery-dl.conf

@@ -159,9 +159,8 @@
         },
         "instagram":
         {
-            "username": null,
-            "password": null,
             "api": "auto",
+            "cookies": null,
             "include": "posts",
             "sleep-request": [6.0, 12.0],
             "videos": true