feat(pdf): optimize formula parsing and update pdfminer.six

- Improve formula parsing success rate for better formula rendering
- Upgrade pdfminer.six to the latest version to fix PDF parsing issues- Update changelog in both English and Chinese README files

README.md

@@ -48,6 +48,9 @@ Easier to use: Just grab MinerU Desktop. No coding, no login, just a simple inte
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 # Changelog
+- 2025/04/27 1.3.9 Released  
+  - Optimized the formula parsing function to improve the success rate of formula rendering  
+  - Updated `pdfminer.six` to the latest version, fixing some abnormal PDF parsing issues
 - 2025/04/23 1.3.8 Released
   - The default `ocr` model (`ch`) has been updated to `PP-OCRv4_server_rec_doc` (model update required)
     - `PP-OCRv4_server_rec_doc` is trained on a mix of more Chinese document data and PP-OCR training data, enhancing recognition capabilities for some traditional Chinese characters, Japanese, and special characters. It supports over 15,000 recognizable characters, improving text recognition in documents while also boosting general text recognition.

README_zh-CN.md

@@ -47,6 +47,9 @@
 </div>
 
 # 更新记录
+- 2025/04/27 1.3.9 发布
+  - 优化公式解析功能，提升公式渲染的成功率
+  - 更新`pdfminer.six`到最新版本，修复了部分pdf解析异常问题
 - 2025/04/23 1.3.8 发布
   - `ocr`默认模型(`ch`)更新为`PP-OCRv4_server_rec_doc`（需更新模型）
     - `PP-OCRv4_server_rec_doc`是在`PP-OCRv4_server_rec`的基础上，在更多中文文档数据和PP-OCR训练数据的混合数据训练而成，增加了部分繁体字、日文、特殊字符的识别能力，可支持识别的字符为1.5万+，除文档相关的文字识别能力提升外，也同时提升了通用文字的识别能力。