Update README.md

Corrected the link ...

README.md

@@ -13,7 +13,7 @@ Install [manually](https://github.com/gorhill/uMatrix/blob/master/doc/README.md)
 
 You may contribute with translation work:
 - For in-app strings, on Crowdin: [uMatrix on Crowdin](https://crowdin.com/project/umatrix).
-- For [description](https://github.com/gorhill/uMatrix/tree/master/doc/description) (to be used in AMO, Chrome store, etc.), submit a pull request. [Reference description is here](https://github.com/gorhill/uMatrix/blob/master/doc/description/description.en_US.txt) (feel free to improve as you wish, I am not a writer).
+- For [description](https://github.com/gorhill/uMatrix/tree/master/doc/description) (to be used in AMO, Chrome store, etc.), submit a pull request. [Reference description is here](https://github.com/gorhill/uMatrix/blob/master/doc/description/description.txt) (feel free to improve as you wish, I am not a writer).
 
 [HTTP Switchboard's documentation](https://github.com/gorhill/httpswitchboard/wiki) is still relevant, except for [uMatrix's differences with HTTP Switchboard](https://github.com/gorhill/uMatrix/wiki/Changes-from-HTTP-Switchboard).