Fix the doc comment

diesel/src/pg/expression/functions.rs

@@ -961,7 +961,7 @@ define_sql_function! {
 
 #[cfg(feature = "postgres_backend")]
 define_sql_function! {
-    /// Returns a text representation of the array's dimensions
+    /// Returns the total number of elements in the array, or 0 if the array is empty.
     ///
     /// # Example
     ///
@@ -975,19 +975,19 @@ define_sql_function! {
     /// #   use diesel::dsl::cardinality;
     /// #   use diesel::sql_types::{Nullable,Array,Integer};
     /// #   let connection = &mut establish_connection();
-    /// 
+    ///
     /// let array_cardinality = diesel::select(cardinality::<Array<Integer>, _>(vec![1, 2, 3, 4]))
     ///     .get_result::<Option<i32>>(connection)?;
     /// assert_eq!(4, array_cardinality.unwrap());
-    /// 
+    ///
     /// let array_cardinality = diesel::select(cardinality::<Array<Nullable<Integer>>, _>(vec![Some(1), Some(2), Some(3)]))
     ///     .get_result::<Option<i32>>(connection)?;
     /// assert_eq!(3, array_cardinality.unwrap());
     ///
     /// let array_cardinality = diesel::select(cardinality::<Array<Integer>, _>(Vec::<i32>::new()))
     ///     .get_result::<Option<i32>>(connection)?;
     /// assert_eq!(0, array_cardinality.unwrap());
-    /// 
+    ///
     /// let array_cardinality = diesel::select(cardinality::<Nullable<Array<Integer>>, _>(None::<Vec<i32>>))
     ///     .get_result::<Option<i32>>(connection)?;
     /// assert_eq!(None, array_cardinality);