Fix typo in Window class.

"event as" -> "events will be"

(cherry picked from commit 112977be262256b5cd3ac6713557dba74d905f44)

doc/classes/Window.xml

@@ -530,7 +530,7 @@
 			[b]Note:[/b] Fullscreen mode is not exclusive full screen on Windows and Linux.
 		</member>
 		<member name="mouse_passthrough" type="bool" setter="set_flag" getter="get_flag" default="false">
-			If [code]true[/code], all mouse event as passed to the underlying window of the same application. See also [member mouse_passthrough_polygon].
+			If [code]true[/code], all mouse events will be passed to the underlying window of the same application. See also [member mouse_passthrough_polygon].
 			[b]Note:[/b] This property is implemented on Linux (X11), macOS and Windows.
 		</member>
 		<member name="mouse_passthrough_polygon" type="PackedVector2Array" setter="set_mouse_passthrough_polygon" getter="get_mouse_passthrough_polygon" default="PackedVector2Array()">