chore: tweak pg_dump error layout

Author: tianzhou

content/reference/postgres/error/_layout.md

@@ -1,6 +1,5 @@
 ---
 # expand_section_list is the list of default expanded sections.
-expand_section_list: ['pg_dump']
 ---
 
 ## [Overview](/reference/postgres/error/overview)
@@ -13,6 +12,4 @@ expand_section_list: ['pg_dump']
 
 ## [42501: permission denied for table](/reference/postgres/error/42501-permission-denied-for-table-postgres)
 
-## pg_dump
-
-### [error: aborting because of server version mismatch](/reference/postgres/error/pgdump-aborting-because-of-server-version-mismatch)
+## [pg_dump: error: aborting because of server version mismatch](/reference/postgres/error/pgdump-aborting-because-of-server-version-mismatch)