docs: fix reBot B601 MDX build (move JSON example out of <Tip>)

The doc-builder parses `{...}` inside MDX component children as a
Svelte expression, so the joint_directions JSON example broke the
build. Move it into a top-level fenced code block.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/source/rebot_b601.mdx

@@ -156,11 +156,21 @@ lerobot-teleoperate \
 <Tip>
   The leader and follower share the same joint names
   (`shoulder_pan, shoulder_lift, elbow_flex, wrist_flex, wrist_yaw, wrist_roll, gripper`),
-  so leader actions map directly onto the follower. If the motion of a joint is
+  so leader actions map directly onto the follower.
-  reversed, flip its sign in `joint_directions` — e.g.
-  `--teleop.joint_directions='{"shoulder_pan":-1,"shoulder_lift":-1,"elbow_flex":1,"wrist_flex":1,"wrist_yaw":1,"wrist_roll":-1,"gripper":-6}'`.
 </Tip>
 
+If the motion of a joint is reversed, flip its sign in the leader's `joint_directions` (the gripper also carries a scale to widen its range to the follower):
+
+```bash
+lerobot-teleoperate \
+    --robot.type=rebot_b601_follower \
+    --robot.port=/dev/ttyACM0 \
+    --robot.can_adapter=damiao \
+    --teleop.type=rebot_102_leader \
+    --teleop.port=/dev/ttyUSB0 \
+    --teleop.joint_directions='{"shoulder_pan":-1,"shoulder_lift":-1,"elbow_flex":1,"wrist_flex":1,"wrist_yaw":1,"wrist_roll":-1,"gripper":-6}'
+```
+
 ## Recording datasets
 
 Swap `lerobot-teleoperate` for `lerobot-record` (with the same `--robot.*` / `--teleop.*` arguments, plus `--dataset.*`) to record demonstrations for training. See [Imitation Learning for Robots](./il_robots) for the full workflow.