Addressing review comments

Change-type: patch
Signed-off-by: Gareth Davies <gareth@balena.io>

README.md

@@ -218,7 +218,7 @@ root@resin:/etc/udev/rules.d# cat 64.rules | jq -sR .
 "ACTION!=\"add|change\", GOTO=\"modeswitch_rules_end\"\nKERNEL==\"ttyACM*\", ATTRS{idVendor}==\"1546\", ATTRS{idProduct}==\"1146\", TAG+=\"systemd\", ENV{SYSTEMD_WANTS}=\"u-blox-switch@'%E{DEVNAME}'.service\"\nLBEL=\"modeswitch_rules_end\"\n"
 ```
 
-The following example contains two custom udev rules that will create `/etc/udev/rules.d/56.rules` and `/etc/udev/rules.d/64.rules`. The first time rules are added/modified, udevd will reload the rules and re-trigger.
+The following example contains two custom udev rules that will create `/etc/udev/rules.d/56.rules` and `/etc/udev/rules.d/64.rules`. The first time rules are added, or when they are modified, udevd will reload the rules and re-trigger.
 
 ```json
 "os": {