[e621] implement 'notes' and 'pools' metadata extraction

(#3425)

docs/configuration.rst

@@ -1103,8 +1103,21 @@ Description
     follow the ``source`` and download from there if possible.
 
 
-extractor.danbooru.metadata
----------------------------
+extractor.danbooru.ugoira
+-------------------------
+Type
+    ``bool``
+Default
+    ``false``
+Description
+    Controls the download target for Ugoira posts.
+
+    * ``true``: Original ZIP archives
+    * ``false``: Converted video files
+
+
+extractor.[Danbooru].metadata
+-----------------------------
 Type
     * ``bool``
     * ``string``
@@ -1125,8 +1138,8 @@ Description
     Note: This requires 1 additional HTTP request per post.
 
 
-extractor.danbooru.threshold
-----------------------------
+extractor.{Danbooru].threshold
+------------------------------
 Type
     * ``string``
     * ``integer``
@@ -1135,27 +1148,13 @@ Default
 Description
     Stop paginating over API results if the length of a batch of returned
     posts is less than the specified number. Defaults to the per-page limit
-    of the current instance, which is 320 for ``e621`` and 200 for
-    everything else.
+    of the current instance, which is 200.
 
     Note: Changing this setting is normally not necessary. When the value is
     greater than the per-page limit, gallery-dl will stop after the first
     batch. The value cannot be less than 1.
 
 
-extractor.danbooru.ugoira
--------------------------
-Type
-    ``bool``
-Default
-    ``false``
-Description
-    Controls the download target for Ugoira posts.
-
-    * ``true``: Original ZIP archives
-    * ``false``: Converted video files
-
-
 extractor.derpibooru.api-key
 ----------------------------
 Type
@@ -1388,6 +1387,40 @@ Description
     Minimum wait time in seconds before API requests.
 
 
+extractor.[E621].metadata
+-------------------------
+Type
+    * ``bool``
+    * ``string``
+    * ``list`` of ``strings``
+Default
+    ``false``
+Example
+    * ``notes,pools``
+    * ``["notes", "pools"``
+Description
+    Extract additional metadata (notes, pool metadata) if available.
+
+    Note: This requires 0-2 additional HTTP requests per post.
+
+
+extractor.[E621].threshold
+--------------------------
+Type
+    * ``string``
+    * ``integer``
+Default
+    ``"auto"``
+Description
+    Stop paginating over API results if the length of a batch of returned
+    posts is less than the specified number. Defaults to the per-page limit
+    of the current instance, which is 320.
+
+    Note: Changing this setting is normally not necessary. When the value is
+    greater than the per-page limit, gallery-dl will stop after the first
+    batch. The value cannot be less than 1.
+
+
 extractor.exhentai.domain
 -------------------------
 Type