update docs

docs/EN/source/method_tutorials/step_distill.md

-# 🚀 Step Distillation
+# Step Distillation
 
 Step distillation is an important optimization technique in LightX2V. By training distilled models, it significantly reduces inference steps from the original 40-50 steps to **4 steps**, dramatically improving inference speed while maintaining video quality. LightX2V implements step distillation along with CFG distillation to further enhance inference speed.
 

docs/ZH_CN/source/method_tutorials/step_distill.md

-# 🚀 步数蒸馏
+# 步数蒸馏
 
 步数蒸馏是 LightX2V 中的一项重要优化技术，通过训练蒸馏模型将推理步数从原始的 40-50 步大幅减少到 **4 步**，在保持视频质量的同时显著提升推理速度。LightX2V 在实现步数蒸馏的同时也加入了 CFG 蒸馏，进一步提升推理速度。