Update README.md (#861)

Fix parenthesis missing, thus logo was not showing up

Author: himan7991

README.md

@@ -2,7 +2,7 @@ This is my top-starred repository on Github, so I've decided to put this ad here
 
 If you work for big corp and seek consulting, please visit following repository: https://github.com/sheerun/consultation
 
-![vim-polyglot](https://i.imgur.com/9RxQK6k.png
+![vim-polyglot](https://i.imgur.com/9RxQK6k.png)
 
 A collection of language packs for Vim.