regclass and format('%I')

Hi All,

The difference in how format handles `regclass` and `name` seems like an
inconsistency:

WITH conversions(casts, format, result) AS (
VALUES (ARRAY['name']::regtype[], '%I', format('%I',
name('select'))),
(ARRAY['name']::regtype[], '%L', format('%L',
name('select'))),
(ARRAY['name']::regtype[], '%s', format('%s',
name('select'))),
(ARRAY['regclass']::regtype[], '%I', format('%I',
regclass('select'))),
(ARRAY['regclass']::regtype[], '%L', format('%L',
regclass('select'))),
(ARRAY['regclass']::regtype[], '%s', format('%s',
regclass('select'))),
(ARRAY['regclass', 'name']::regtype[], '%I', format('%I',
name(regclass('select')))),
(ARRAY['regclass', 'name']::regtype[], '%L', format('%L',
name(regclass('select')))),
(ARRAY['regclass', 'name']::regtype[], '%s', format('%s',
name(regclass('select'))))
) SELECT * FROM conversions;
casts | format | result
-----------------+--------+--------------
{name} | %I | "select"
{name} | %L | 'select'
{name} | %s | select
{regclass} | %I | """select"""
{regclass} | %L | '"select"'
{regclass} | %s | "select"
{regclass,name} | %I | """select"""
{regclass,name} | %L | '"select"'
{regclass,name} | %s | "select"

My assumption is that they both represent valid SQL identifiers, so it stands
to reason that `%I` should result in a valid identifier for both of them (or
neither one).

Kind Regards,
Jason Dusek