For those trying to add a shortcut for the Reroute node, this works inside EditorPerProjectUserSettings.ini
[BlueprintSpawnNodes]
Node=(Class=K2Node_Knot Key=R Shift=false Ctrl=false Alt=false)
while this works inside BaseEditorPerProjectUserSettings.ini
[BlueprintSpawnNodes]
<other shortcuts>
+Node=(Class=K2Node_Knot Key=R Shift=false Ctrl=false Alt=false)
Tested with 4.23.1