Update COMMENT ON docs for types

Fixes DOC-10455

src/current/v24.2/comment-on.md

@@ -1,11 +1,11 @@
 ---
 title: COMMENT ON
-summary: The COMMENT ON statement associates comments to databases, tables, columns, or indexes.
+summary: The COMMENT ON statement associates comments to databases, tables, columns, indexes, or types.
 toc: true
 docs_area: reference.sql
 ---
 
-The `COMMENT ON` [statement]({% link {{ page.version.version }}/sql-statements.md %}) associates comments to [databases]({% link {{ page.version.version }}/create-database.md %}), [tables]({% link {{ page.version.version }}/create-table.md %}), [columns]({% link {{ page.version.version }}/alter-table.md %}#add-column), or [indexes]({% link {{ page.version.version }}/indexes.md %}).
+The `COMMENT ON` [statement]({% link {{ page.version.version }}/sql-statements.md %}) associates comments to [databases]({% link {{ page.version.version }}/create-database.md %}), [tables]({% link {{ page.version.version }}/create-table.md %}), [columns]({% link {{ page.version.version }}/alter-table.md %}#add-column), [indexes]({% link {{ page.version.version }}/indexes.md %}), or [types]({% link {{page.version.version}}/show-types.md %}).
 
 {% include {{ page.version.version }}/misc/schema-change-stmt-note.md %}
 
@@ -25,6 +25,7 @@ The user must have the `CREATE` [privilege]({% link {{ page.version.version }}/s
 ------------|--------------
 `database_name` | The name of the [database]({% link {{ page.version.version }}/create-database.md %}) on which you are commenting.
 `schema_name` |  The name of the [schema]({% link {{ page.version.version }}/create-schema.md %}) on which you are commenting.
+`type_name` | The name of the [type]({% link {{ page.version.version }}/show-types.md %}) on which you are commenting.
 `table_name` | The name of the [table]({% link {{ page.version.version }}/create-table.md %}) on which you are commenting.
 `column_name` | The name of the [column]({% link {{ page.version.version }}/alter-table.md %}#add-column) on which you are commenting.
 `table_index_name` | The name of the [index]({% link {{ page.version.version }}/indexes.md %}) on which you are commenting.
@@ -180,6 +181,22 @@ To view column comments, use [`SHOW INDEXES ... WITH COMMENT`]({% link {{ page.v
 (8 rows)
 ~~~
 
+### Add a comment to a type
+
+Suppose we [create a type]({% link {{ page.version.version }}/create-type.md %}):
+
+{% include_cached copy-clipboard.html %}
+~~~ sql
+CREATE TYPE IF NOT EXISTS my_point AS (x FLOAT, y FLOAT, z FLOAT);
+~~~
+
+{% include_cached copy-clipboard.html %}
+~~~ sql
+COMMENT ON TYPE my_point IS '3D point';
+~~~
+
+[XXX](): how to view the type?
+
 ### Remove a comment from a database
 
 To remove a comment from a database: