syncthing.sh, README.md: change syncthing menu to 0-based indexing

README.md

@@ -121,16 +121,16 @@ Entry point. Presents a menu:
 
 ### `syncthing.sh`
 Interactive Syncthing management. Can be run on the hub or any spoke. Presents a menu:
-- 1) Show This Device's ID
-- 2) Pending Devices
-- 3) List Devices
-- 4) Add Device
-- 5) Remove Device
-- 6) List Folders
-- 7) Add Folder
-- 8) Remove Folder
-- 9) Share Folder with Device
-- 10) Unshare Folder from Device
+- 0) Show This Device's ID
+- 1) Pending Devices
+- 2) List Devices
+- 3) Add Device
+- 4) Remove Device
+- 5) List Folders
+- 6) Add Folder
+- 7) Remove Folder
+- 8) Share Folder with Device
+- 9) Unshare Folder from Device
 
 Requires Docker and a running Syncthing container. Auto-discovers the container and API key.