fix error in docs

parquet/src/file/metadata/mod.rs

@@ -837,7 +837,7 @@ impl ColumnChunkMetaData {
     /// Returns the definition level histogram.
     ///
     /// The returned value `vec[i]` is how many values are at definition level `i`. For example,
-    /// `vec[max_definition_level-1]` indicates how many non-null values are present in the page.
+    /// `vec[max_definition_level]` indicates how many non-null values are present in the page.
     /// This field may not be set by older writers.
     pub fn definition_level_histogram(&self) -> Option<&LevelHistogram> {
         self.definition_level_histogram.as_ref()

parquet/src/file/page_index/index.rs

@@ -44,7 +44,7 @@ pub struct PageIndex<T> {
     /// Definition level histogram for the page
     ///
     /// `definition_level_histogram[i]` is a count of how many values are at definition level `i`.
-    /// For example, `definition_level_histogram[max_definition_level-1]` indicates how many
+    /// For example, `definition_level_histogram[max_definition_level]` indicates how many
     /// non-null values are present in the page.
     pub definition_level_histogram: Option<Vec<i64>>,
 }