[downloader:http] add 'retry-codes' option (#3313)

docs/configuration.rst

@@ -3280,6 +3280,24 @@ Description
     Additional HTTP headers to send when downloading files,
 
 
+downloader.http.retry-codes
+---------------------------
+Type
+    ``list`` of ``integers``
+Default
+    ``[429]``
+Description
+    Additional `HTTP response status codes <https://developer.mozilla.org/en-US/docs/Web/HTTP/Status>`__
+    to retry a download on.
+
+    Codes ``200``, ``206``, and ``416`` (when resuming a `partial <downloader.*.part_>`__
+    download) will never be retried and always count as success,
+    regardless of this option.
+
+    Codes ``500`` - ``599`` (server error responses)  will always be retried,
+    regardless of this option.
+
+
 downloader.ytdl.format
 ----------------------
 Type