Update CONTRIBUTING.md

Author: khatchad

CONTRIBUTING.md

@@ -14,7 +14,7 @@ Each time we run the evaluation, a text file is generated in the working directo
 
 You should have the following projects in your workspace:
 
-1. [WALA stream branch](https://github.com/ponder-lab/WALA/tree/streams). Though, not all projecst are necessary. You can close thee ones related to JavaScript and Android.
+1. [WALA streams branch](https://github.com/ponder-lab/WALA/tree/streams). Though, not all projecst are necessary. You can close thee ones related to JavaScript and Android.
 1. [SAFE](https://github.com/ponder-lab/safe).
 1. [Common Eclipse Java Refactoring Framework](https://github.com/ponder-lab/Common-Eclipse-Java-Refactoring-Framework).