Update README.md

Changed KSstring Entity property description to reflect ability to use reltime() function for relative time.

README.md

@@ -116,7 +116,7 @@ This is a string value containing dynamic values. Data for dynamic values can be
 | Type | Example | Description |
 |:-----|:-----|:-----|
 | Charging state | `"{charging}"` | Shows text specified in [ChargingState](#charging-state-object)
-| Entity property | `"{last_updated}"` | Current entity property. To show relative time there cannot be any additional string befor/after the keyword otherwise it will show full date.
+| Entity property | `"{last_updated}"` | Current entity property. To ensure relative time, use the reltime() function via "\|" (see below). E.g.: `"Changed: {last_updated\|reltime()}"`
 | Entity attributes | `"Remaining time: {attributes.remaining_time}"` | Current entity attribute value.
 | Other entity data | `"Since last charge: {sensor.tesla.attributes.distance}"` | You can use full "path" to the other entity data