Correct doc comment

Author: pepijnve

arrow-select/src/merge.rs

@@ -24,9 +24,9 @@ use arrow_data::ArrayData;
 use arrow_data::transform::MutableArrayData;
 use arrow_schema::ArrowError;
 
-/// An index for the [merge] function.
+/// An index for the [merge_n] function.
 ///
-/// This trait allows the indices argument for [merge] to be stored using a more
+/// This trait allows the indices argument for [merge_n] to be stored using a more
 /// compact representation than `usize` when the input arrays are small.
 /// If the number of input arrays is less than 256 for instance, the indices can be stored as `u8`.
 ///