Update docs

docs/getting-started-installation.md

@@ -13,7 +13,7 @@ We have created an easy script that will get all of the infrastructure set up fo
 
     > You have to be on Node >= 8.x and Yarn >= 1.5.
 
-1.  Create a project, if none exists, and change your the directory to this project's root.
+1.  Create a project, if none exists, and change your directory to this project's root.
 
     You will be creating the docs in this directory. The root directory may
     contain other files. The Docusaurus installation script will create two new