Print number of worker threads when display level is >= 2

programs/zstdcli.c

@@ -1311,6 +1311,7 @@ int main(int argCount, const char* argv[])
             DISPLAYLEVEL(3, "Note: %d physical core(s) detected \n", nbWorkers);
         }
     }
+    DISPLAYLEVEL(2, "Compressing with %u worker threads \n", nbWorkers);
 #else
     (void)singleThread; (void)nbWorkers; (void)defaultLogicalCores;
 #endif