bench readme: fix typo from prior commit
@@ -53,7 +53,7 @@ garbage as a factor of the benchmark.
`-disable-idempotency` disables producing idempotently, which limits the throughput to 1rps
-`-ling` sets an amount of milliseconds to linger before producing, overriding the default 0.
+`-linger` sets an amount of milliseconds to linger before producing, overriding the default 0.
### Consuming (only relevant if consuming)
