fix: failure chain

README.rst

@@ -185,6 +185,8 @@ Other options:
                             timeout for downloading doujinshi
       -d DELAY, --delay=DELAY
                             slow down between downloading every doujinshi
+      --retry=RETRY         retry times when downloading failed
+      --exit-on-fail        exit on fail to prevent generating incomplete files
       --proxy=PROXY         store a proxy, for example: -p "http://127.0.0.1:1080"
       -f FILE, --file=FILE  read gallery IDs from file.
       --format=NAME_FORMAT  format the saved folder name