sql: pretty-printing of partition clauses is incorrect

[knz]

Epic: CRDB-17785
Found via #95239.

Describe the problem

When partition names or columns contain special characters, the output of SHOW CREATE is invalid SQL syntax.

For example:

[email protected]:26257/movr> create table foo("a b" name not null, index ("a b") partition by list ("a b") (partition foo values in ('ab')));
CREATE TABLE

Time: 6ms total (execution 6ms / network 0ms)

[email protected]:26257/movr> show create table foo;
  table_name |                       create_statement
-------------+----------------------------------------------------------------
  foo        | CREATE TABLE public.foo (
             |     "a b" NAME NOT NULL,
             |     rowid INT8 NOT VISIBLE NOT NULL DEFAULT unique_rowid(),
             |     CONSTRAINT foo_pkey PRIMARY KEY (rowid ASC),
             |     INDEX "foo_a b_idx" ("a b" ASC) PARTITION BY LIST (a b) (
             |         PARTITION foo VALUES IN (('ab'))
             |     )
             | )

The identifier inside PARTITION BY LIST is improperly quoted.

Jira issue: CRDB-23416