update en/contribute/writing-instructions.md.

Signed-off-by: NYangys <yangyousheng@huawei.com>

en/contribute/writing-instructions.md

@@ -69,7 +69,7 @@ Use relative paths to reference pictures in the document.
 -   The text on pictures should be Chinese in Chinese documents and English in English documents.
 -   It is recommended that pictures be named based on the content. Using only a number is difficult for picture inheritance.
 
->**NOTE:** 
+>![](public_sys-resources/icon-note.gif) **NOTE:** 
 >Reference:
 >!\[\]\(./pic/pic-standard.png\)