Merge pull request #15745 from Microsoft/readme

Update readme

README.md

@@ -1,12 +1,12 @@
-Docker: the Linux container engine
-==================================
+Docker: the container engine
+============================
 
 Docker is an open source project to pack, ship and run any application
 as a lightweight container.
 
 Docker containers are both *hardware-agnostic* and *platform-agnostic*.
 This means they can run anywhere, from your laptop to the largest
-EC2 compute instance and everything in between - and they don't require
+cloud compute instance and everything in between - and they don't require
 you to use a particular language, framework or packaging system. That
 makes them great building blocks for deploying and scaling web apps,
 databases, and backend services without depending on a particular stack