fix doc

kernel/src/actions/mod.rs

@@ -143,7 +143,7 @@ pub struct Add {
     /// A map from partition column to value for this logical file. This map can contain null in the
     /// values meaning a partition is null. We drop those values from this map, due to the
     /// `drop_null_container_values` annotation. This means an engine can assume that if a partition
-    /// is found in [`Metadata`] `partition_columns`, but not in this map, it's value is null.
+    /// is found in [`Metadata`] `partition_columns`, but not in this map, its value is null.
     #[drop_null_container_values]
     pub partition_values: HashMap<String, String>,