Replace Jev card nav: drop API, rename Demo to Usage.

README.md

@@ -16,7 +16,7 @@ tags:
 
 <div align="center">
 
-[GitHub](https://github.com/OpenBMB/MiniCPM-OCR) · [API](https://github.com/OpenBMB/MiniCPM-OCR/blob/main/docs/minicpm_ocr_jev_api_en.md) · [Demo](https://platform.modelbest.ai/console/playground/document-parse)
+[GitHub](https://github.com/OpenBMB/MiniCPM-OCR) · [Usage](https://github.com/OpenBMB/MiniCPM-OCR/blob/main/docs/minicpm_ocr_jev_tutorial_en.md)
 
 </div>