add hint when install shapely on win

doc/doc_ch/installation.md

@@ -80,3 +80,6 @@ git clone https://gitee.com/paddlepaddle/PaddleOCR
 cd PaddleOCR
 pip3 install -r requirments.txt
 ```
+
+注意，windows环境下，建议从[这里](https://www.lfd.uci.edu/~gohlke/pythonlibs/#shapely)下载shapely安装包完成安装，
+直接通过pip安装的shapely库可能出现`[winRrror 126] 找不到指定模块的问题`。

doc/doc_en/installation_en.md

@@ -82,3 +82,9 @@ git clone https://gitee.com/paddlepaddle/PaddleOCR
 cd PaddleOCR
 pip3 install -r requirments.txt
 ```
+
+If you getting this error `OSError: [WinError 126] The specified module could not be found` when you install shapely on windows.
+
+Please try to download Shapely whl file using [http://www.lfd.uci.edu/~gohlke/pythonlibs/#shapely](http://www.lfd.uci.edu/~gohlke/pythonlibs/#shapely).
+
+Reference: [Solve shapely installation on windows](https://stackoverflow.com/questions/44398265/install-shapely-oserror-winerror-126-the-specified-module-could-not-be-found)