rev-list-options.txt: fix simple typo

Signed-off-by: Elijah Newren <newren@gmail.com>
Acked-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/rev-list-options.txt

@@ -659,7 +659,7 @@ Here, the merge commits `O` and `P` contribute extra noise, as they did
 not actually contribute a change to `file.txt`. They only merged a topic
 that was based on an older version of `file.txt`. This is a common
 issue in repositories using a workflow where many contributors work in
-parallel and merge their topic branches along a single trunk: manu
+parallel and merge their topic branches along a single trunk: many
 unrelated merges appear in the `--full-history` results.
 
 When using the `--simplify-merges` option, the commits `O` and `P`