Update descriptions

doc/doc_ch/data_synthesis.md

-## 数据合成工具
+# 数据合成工具
+
 除了开源数据，用户还可使用合成工具自行合成。这里整理了常用的数据合成工具，持续更新中，欢迎各位小伙伴贡献工具～
+
 - [text_renderer](https://github.com/Sanster/text_renderer)
 - [SynthText](https://github.com/ankush-me/SynthText)
 - [SynthText_Chinese_version](https://github.com/JarveeLee/SynthText_Chinese_version)
 - [TextRecognitionDataGenerator](https://github.com/Belval/TextRecognitionDataGenerator)
 - [SynthText3D](https://github.com/MhLiao/SynthText3D)
 - [UnrealText](https://github.com/Jyouhou/UnrealText/)
+- [SynthTIGER](https://github.com/clovaai/synthtiger)

doc/doc_en/data_synthesis_en.md

@@ -3,9 +3,10 @@
 In addition to open source data, users can also use synthesis tools to synthesize data.
 There are the commonly used data synthesis tools, which will be continuously updated. Welcome to contribute tools~
 
-*  [Text_renderer](https://github.com/Sanster/text_renderer)
+* [Text_renderer](https://github.com/Sanster/text_renderer)
 * [SynthText](https://github.com/ankush-me/SynthText)
 * [SynthText_Chinese_version](https://github.com/JarveeLee/SynthText_Chinese_version)
 * [TextRecognitionDataGenerator](https://github.com/Belval/TextRecognitionDataGenerator)
 * [SynthText3D](https://github.com/MhLiao/SynthText3D)
 * [UnrealText](https://github.com/Jyouhou/UnrealText/)
+* [SynthTIGER](https://github.com/clovaai/synthtiger)