Update installing-nginx-plus-amazon-web-services.md (#495)

Removed the gerund from the "Install the F5 NGINX Plus AMI" header.

Author: apgordon312

content/nginx/admin-guide/installing-nginx/installing-nginx-plus-amazon-web-services.md

@@ -16,7 +16,7 @@ The AMIs contain the following components:
 - Latest version of [NGINX Plus](https://www.f5.com/products/nginx/nginx-plus), optimized for use on Amazon EC2
 - Pre-packaged software for building highly available (HA) NGINX Plus configurations
 
-## Installing the F5 NGINX Plus AMI
+## Install the F5 NGINX Plus AMI
 
 To quickly set up an NGINX Plus environment on AWS: