RX, TX say dB

Rpm say "turns per minutes"
AccXYZ say "g"
Hdg say degrees
VSpd say  m/s
Alt- say meters
Alt+ say meters
Rpm+ say "turns/minure"
A1/A2 and A1-/A2- say the chosen unit
A1- and A2- say the right value

src/model_menus.cpp

@@ -2881,7 +2881,7 @@ void menuProcTelemetry(uint8_t event)
             }
           }
           else {
-            CHECK_INCDEC_MODELVAR(event, channel.type, 0, UNIT_MAX-1);
+            CHECK_INCDEC_MODELVAR(event, channel.type, 0, UNIT_A1A2_MAX);
           }
         }
         break;