fix missing "s" in Viewport docs

doc/classes/Viewport.xml

@@ -213,7 +213,7 @@
 			The global canvas transform of the viewport. The canvas transform is relative to this.
 		</member>
 		<member name="gui_disable_input" type="bool" setter="set_disable_input" getter="is_input_disabled" default="false">
-			If [code]true[/code], the viewport will not receive input event.
+			If [code]true[/code], the viewport will not receive input events.
 		</member>
 		<member name="gui_embed_subwindows" type="bool" setter="set_embed_subwindows_hint" getter="get_embed_subwindows_hint" default="false">
 		</member>