update doc

Author: molpopgen

src/table_column.rs

@@ -1,6 +1,6 @@
 macro_rules! make_table_column {
     ($name: ident, $index: ident) => {
-        /// Immutable view of a column
+        /// Immutable view of a (non-ragged) column
         #[derive(Clone, Debug)]
         #[repr(transparent)]
         pub struct $name<'table, T>(&'table [T]);