LteCommonEnum.msg: figured out what LteTrafficClass is, added comment

Author: avarga

src/simu5g/common/LteCommonEnum.msg

@@ -43,6 +43,7 @@ enum RbAllocationType
 };
 
 /// Lte Traffic Classes
+/// This is the fringing LCG index (sent in BSRs). NR has 8 (as opposed to LTE's 4, but then, so what??)
 enum LteTrafficClass
 {
     CONVERSATIONAL = 0; STREAMING =1;  INTERACTIVE = 2; BACKGROUND = 3; UNKNOWN_TRAFFIC_TYPE = 4;