fixed spelling

Author: john-chrosniak

tutorials/docs/navigation2_route_tool.rst

@@ -45,7 +45,7 @@ Loading a Route Graph
 
 To load in an existing route graph, click on the load button on the bottom left of the route tool panel.
 This will open up a file explorer so you can navigate to the existing geojson file you would like to load.
-After clicking open, you should see the route graph overlayed with your occupancy grid map.
+After clicking open, you should see the route graph overlaid with your occupancy grid map.
 
 Adding Nodes and Edges
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