message: Update README.md
  Added missing backtick
diff: @@ -480,7 +480,7 @@ follow `--` in tarpaulin use `args` in the toml file.
  Setting the field `config` will have no effect on the run as it won't be parsed
  for additional configuration.
  -For the flags `--lib`, `--examples`, `--benches, `--tests`, `--all-targets`,
  +For the flags `--lib`, `--examples`, `--benches`, `--tests`, `--all-targets`,
  `--doc`, `--bins` use the `run-types` entry in the config file.
  ## Extending Tarpaulin
  