[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

docs/how_it_works.md

@@ -203,7 +203,7 @@ For example `nw.col("b")._call(nwdf.__narwhals_namespace__())` on a
 `pyarrow.Table` will return an `ArrowExpr`:
 
 ```python
-  ArrowExpr(depth=0, function_name=col, root_names=['b'], output_names=['b']
+ArrowExpr(depth=0, function_name=col, root_names=['b'], output_names=['b']
 ```
 
 but invoking `narwhals.Dataframe.select` on it will work and return