Merge pull request #2123 from andrum99/patch-2

Update graphics-utilities.adoc

Author: Alasdair Allan

documentation/asciidoc/computers/os/graphics-utilities.adoc

@@ -138,7 +138,8 @@ Returns the throttled state of the system. This is a bit pattern - a bit being s
 
 ==== measure_temp
 
-Returns the temperature of the SoC as measured by the on-board temperature sensor.
+Returns the temperature of the SoC as measured by its internal temperature sensor;
+on Raspberry Pi 4, `measure_temp pmic` returns the temperature of the PMIC.
 
 ==== measure_clock [clock]