Replace curly-brace placeholders with angle-bracket form to match the convention used elsewhere:

• {GPU node ip} -> <GPU-node-ip> in real-time-device-usage.md
• {scheduler node ip} -> <scheduler-ip> in device-allocation.md
• {volcano scheduler cluster ip} -> <scheduler-ip> in monitor.md and both how-to-use-volcano-vgpu.md files
• {node name} -> <node-name> in both how-to-use-volcano-vgpu.md files

Files changed:

• docs/userguide/monitoring/real-time-device-usage.md
• docs/userguide/monitoring/device-allocation.md
• docs/userguide/volcano-vgpu/nvidia-gpu/monitor.md
• docs/userguide/volcano-vgpu/nvidia-gpu/how-to-use-volcano-vgpu.md
• docs/installation/how-to-use-volcano-vgpu.md

Summary by CodeRabbit

• Documentation
  • Improved several user guide and installation examples with clearer placeholder text for cluster node names and IP addresses.
  • Standardized metrics endpoint examples across vGPU and monitoring docs for easier copy-and-paste use.
  • Updated command snippets to use consistent angle-bracket placeholders, making setup and verification steps easier to follow.