doc of filesite.io update

www/content/README.md

@@ -135,8 +135,8 @@ Articles, pictures, and video files other than URLs.
 ```
 
 Special fields:    
-* extname is lower case, case insensitive
 * extension is case sensitive
+* extname is lower case of extension
 
 
 .txt, .md and .url 3 file descriptions:

www/content/en/README.md

@@ -136,8 +136,8 @@ Articles, pictures, and video files other than URLs.
 
 
 Special fields:    
-* extname is lower case, case insensitive
 * extension is case sensitive
+* extname is lower case of extension
 
 
 .txt, .md and .url 3 file descriptions:

www/content/zh-cn/README.md

@@ -135,7 +135,7 @@
 ```
 
 其中：  
-extension区分大小写，extname只有小写。
+extension区分大小写，extname是小写的extension。
 
 
 .txt，.md和.url 3 种文件说明：