applets/batterymonitor: Communicate that charging limits are approximate

Kernel developers have said that charge limits are approximate, not
exact[1]. As a result, if for example you have a charge limit of 80%,
your battery might actually stop charging anywhere between 78-82%. But
if we only list the charge limit itself, it looks to users like a KDE
bug when the battery stops charging at any number other than that limit.

To alleviate that, this commit adjusts the text to indicate that the
charge limit is appropximate.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=215531#c3

applets/batterymonitor/package/contents/ui/BatteryItem.qml

@@ -193,7 +193,7 @@ RowLayout {
             readonly property bool pluggedIn: pmSource.data["AC Adapter"] !== undefined && pmSource.data["AC Adapter"]["Plugged in"]
             visible: pluggedIn && typeof chargeStopThreshold === "number" && chargeStopThreshold > 0 && chargeStopThreshold < 100
             iconSource: "kt-speed-limits" // FIXME good icon
-            text: i18n("Your battery is configured to only charge up to %1%.", chargeStopThreshold || 0)
+            text: i18n("Battery is configured to charge up to approximately %1%.", chargeStopThreshold || 0)
         }
     }
 }