message: [libra_fuzzer] small update to readme
  A friend of mine was playing around with the fuzzer and got confused about this.
diff: @@ -11,6 +11,9 @@ Install [`cargo-fuzz`](https://rust-fuzz.github.io/book/cargo-fuzz.html) if not
  ### Fuzzing a target
  +First, switch to the directory this README is in: `cd
  +testsuite/libra_fuzzer`.
  +
  To list out known fuzz targets, run `cargo run list`.
  To be effective, fuzzing requires a corpus of existing inputs. This
  