Update README.md

Author: wang-chen

README.md

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-### :scroll: AirSLAM [(TRO'25)](https://arxiv.org/pdf/2408.03520) has dual-mode (V-SLAM & VI-SLAM), upgraded from [AirVO (IROS'23)](https://github.com/sair-lab/AirSLAM/releases/tag/1.0)
+### :scroll: AirSLAM [(TRO'25)](https://arxiv.org/pdf/2408.03520) has dual-mode (V-SLAM, VI-SLAM), upgraded from [AirVO (IROS'23)](https://github.com/sair-lab/AirSLAM/releases/tag/1.0)
 
 <p align="middle">
   <img src="figures/system_arch.jpg" width="600" />