fixed cut-and-paste error on description of Docker Toolbox

Signed-off-by: Victoria Bialas <victoria.bialas@docker.com>
(cherry picked from commit 6f9e310831326b8031a3526282ffd82cee94294f)
Signed-off-by: Tibor Vass <tibor@docker.com>

docs/installation/windows.md

@@ -34,7 +34,7 @@ If you have an earlier Windows system that doesn't meet the Docker for Windows r
 
 See [Docker Toolbox Overview](/toolbox/overview.md) for help on installing Docker with Toolbox.
 
-The Docker Toolbox setup does not run Docker natively in OS X. Instead, it uses `docker-machine` to create and attach to a virtual machine (VM). This machine is a Linux VM that hosts Docker for you on your Mac.
+The Docker Toolbox setup does not run Docker natively on Windows. Instead, it uses `docker-machine` to create and attach to a virtual machine (VM). This machine is a Linux VM that hosts Docker for you on your Windows system.
 
 **Requirements**