f print note about what number and g means

src/bench_ecmult.c

@@ -271,6 +271,7 @@ int main(int argc, char **argv) {
     data.scratch = secp256k1_scratch_space_create(data.ctx, scratch_size);
     data.ecmult_multi = secp256k1_ecmult_multi_var;
 
+    printf("Note: In the following output the number after the function name is the number of points that are multiplied. The letter 'g' indicates that one of the points is the generator.\n");
     if (argc > 1) {
         if(have_flag(argc, argv, "pippenger_wnaf")) {
             printf("Using pippenger_wnaf:\n");