why doesn't \d table_name show the table inheritance graph?

The Momjian books shows this:

 test=> CREATE TABLE parent_test (col1 INTEGER);
        CREATE
        test=> CREATE TABLE child_test (col2 INTEGER) INHERITS 
(parent_test);
        CREATE
        test=> \d parent_test
                 Table "parent_test"
         Attribute |  Type   | Modifier 
        -----------+---------+----------
         col1      | integer | 
         
        test=> \d child_test
                 Table "child_test"
         Attribute |  Type   | Modifier 
        -----------+---------+----------
         col1      | integer | 
         col2      | integer |   

but I think it would be very important, to know inheritance as to
know indexes.