Fix partition handling for recent Postgres versions

[seanlinsley]

This PR fixes two issues with partition table handling:

• The attach command for a partition has a comment with Type: TABLE ATTACH which wasn't being matched, leading to a dangling ATTACH in the output, which causes a syntax error.
• The primary key handling was out of date, both for the comment and the ALTER INDEX command.

Without the implementation changes, the added test fails with:

CleanDumpTest#test_partitions [test/clean_dump_test.rb:29]:
--- expected
+++ actual
@@ -17,6 +17,8 @@
 
 CREATE INDEX index_autovacuum_run_stats_35d_on_server_id_and_occurred_at ON public.autovacuum_run_stats_35d USING btree (server_id, occurred_at);
 
+ ATTACH
+
 -- Name: schema_table_infos_35d; Type: TABLE
 
 CREATE TABLE public.schema_table_infos_35d (
@@ -29,4 +31,10 @@
 ALTER TABLE ONLY public.schema_table_infos_35d
     ADD CONSTRAINT schema_table_infos_35d_pkey PRIMARY KEY (schema_table_id, collected_at);
 
+ ATTACH
+
+-- Name: schema_table_infos_35d_20240920_pkey; Type: INDEX ATTACH
+
+ALTER INDEX public.schema_table_infos_35d_pkey ATTACH PARTITION public.schema_table_infos_35d_20240920_pkey;
+
 "