Add comment about order of baggage items (#34527)

Follow up from #33777

Author: shirhatti

src/Hosting/Hosting/src/Internal/HostingApplicationDiagnostics.cs

@@ -307,6 +307,8 @@ private static void RecordRequestStartEventLog(HttpContext httpContext)
                     fieldValue = headers[fieldName];
                 });
 
+                // AddBaggage adds items at the beginning  of the list, so we need to add them in reverse to keep the same order as the client
+                // By contract, the propagator has already reversed the order of items so we need not reverse it again 
                 // Order could be important if baggage has two items with the same key (that is allowed by the contract)
                 if (baggage is not null)
                 {