Fix typo in window guide

Fixes #1099.

docs/window.dox

@@ -87,7 +87,7 @@ By default, the original video mode of the monitor will be restored and the
 window iconified if it loses input focus, to allow the user to switch back to
 the desktop.  This behavior can be disabled with the
 [GLFW_AUTO_ICONIFY](@ref GLFW_AUTO_ICONIFY_hint) window hint, for example if you
-wish to simultaneously cover multiple windows with full screen windows.
+wish to simultaneously cover multiple monitors with full screen windows.
 
 If a monitor is disconnected, any window that is full screen on that monitor
 will be forced into windowed mode.  See @ref monitor_event for more information.