Document more RPC errors

These two occur when replying to an inline query with a photo and
InputBotInlineMessageMediaAuto empty message, and passing URLs to
PNGs that may not be accessible (i.e. 403 from pixiv).

telethon/client/downloads.py

@@ -26,6 +26,16 @@ class DownloadMethods(UserMethods):
             entity (`entity`):
                 From who the photo will be downloaded.
 
+                .. note::
+
+                    This method expects the full entity (which has the data
+                    to download the photo), not an input variant.
+
+                    It's possible that sometimes you can't fetch the entity
+                    from its input (since you can get errors like
+                    ``ChannelPrivateError``) but you already have it through
+                    another call, like getting a forwarded message from it.
+
             file (`str` | `file`, optional):
                 The output file path, directory, or stream-like object.
                 If the path exists and is a file, it will be overwritten.

telethon_generator/data/errors.csv

@@ -166,11 +166,13 @@ PHONE_NUMBER_OCCUPIED,400,The phone number is already in use
 PHONE_NUMBER_UNOCCUPIED,400,The phone number is not yet being used
 PHONE_PASSWORD_FLOOD,406,You have tried logging in too many times
 PHONE_PASSWORD_PROTECTED,400,This phone is password protected
+PHOTO_CONTENT_URL_EMPTY,400,The content from the URL used as a photo appears to be empty or has caused another HTTP error
 PHOTO_CROP_SIZE_SMALL,400,Photo is too small
 PHOTO_EXT_INVALID,400,The extension of the photo is invalid
 PHOTO_INVALID,400,Photo invalid
 PHOTO_INVALID_DIMENSIONS,400,The photo dimensions are invalid
 PHOTO_SAVE_FILE_INVALID,400,The photo you tried to send cannot be saved by Telegram. A reason may be that it exceeds 10MB. Try resizing it locally
+PHOTO_THUMB_URL_EMPTY,400,The URL used as a thumbnail appears to be empty or has caused another HTTP error
 PIN_RESTRICTED,400,You can't pin messages in private chats with other people
 PRIVACY_KEY_INVALID,400,The privacy key is invalid
 PTS_CHANGE_EMPTY,500,No PTS change

telethon_generator/data/methods.csv

@@ -147,7 +147,7 @@ messages.setBotPrecheckoutResults,unknown,ERROR_TEXT_EMPTY
 messages.setBotShippingResults,unknown,QUERY_ID_INVALID
 messages.setEncryptedTyping,user,CHAT_ID_INVALID
 messages.setGameScore,unknown,PEER_ID_INVALID USER_BOT_REQUIRED
-messages.setInlineBotResults,unknown,ARTICLE_TITLE_EMPTY BUTTON_DATA_INVALID BUTTON_TYPE_INVALID BUTTON_URL_INVALID MESSAGE_EMPTY QUERY_ID_INVALID REPLY_MARKUP_INVALID RESULT_TYPE_INVALID SEND_MESSAGE_MEDIA_INVALID SEND_MESSAGE_TYPE_INVALID START_PARAM_INVALID USER_BOT_INVALID
+messages.setInlineBotResults,unknown,ARTICLE_TITLE_EMPTY BUTTON_DATA_INVALID BUTTON_TYPE_INVALID BUTTON_URL_INVALID MESSAGE_EMPTY PHOTO_CONTENT_URL_EMPTY PHOTO_THUMB_URL_EMPTY QUERY_ID_INVALID REPLY_MARKUP_INVALID RESULT_TYPE_INVALID SEND_MESSAGE_MEDIA_INVALID SEND_MESSAGE_TYPE_INVALID START_PARAM_INVALID USER_BOT_INVALID
 messages.setInlineGameScore,unknown,MESSAGE_ID_INVALID USER_BOT_REQUIRED
 messages.setTyping,unknown,CHANNEL_INVALID CHANNEL_PRIVATE CHAT_ID_INVALID CHAT_WRITE_FORBIDDEN PEER_ID_INVALID USER_BANNED_IN_CHANNEL USER_IS_BLOCKED USER_IS_BOT
 messages.startBot,user,BOT_INVALID PEER_ID_INVALID START_PARAM_EMPTY START_PARAM_INVALID