[psteinroe]

Fixes two small formatter bugs found while working on #871.

ALTER DOMAIN operations are indented when the statement breaks

emit_alter_domain_stmt broke the line before the operation without an indent, so a long ALTER DOMAIN put add constraint (and drop constraint, validate constraint, set/drop default, set/drop not null) at column 0. The operation now sits in an indent, the same way ALTER TABLE indents its commands:

-- before
alter domain public.email_address
add constraint email_address_not_blank check (
  value <> '' and value is not null and length(value) > 3
) not valid;

-- after
alter domain public.email_address
  add constraint email_address_not_blank check (
    value <> '' and value is not null and length(value) > 3
  ) not valid;

Short statements still fit on one line (alter domain public.short_domain drop not null;).

No double space before RETURNING in JSON functions

json_value, json_query, json_arrayagg and json_objectagg emit a soft line before RETURNING, then called emit_json_output with has_content = true, which adds its own space. When the group stayed flat, that printed two spaces:

-- before
select json_value(cast('123' as jsonb), '$'  returning int);
select json_arrayagg(i absent on null  returning jsonb) from t;
-- after
select json_value(cast('123' as jsonb), '$' returning int);
select json_arrayagg(i absent on null returning jsonb) from t;

These four call sites no longer ask for the extra space. json_object, json_array, json_serialize, json_parse, the JsonAggConstructor tail and json_table don't emit a line before RETURNING, so they already used a single space and stay unchanged. json_exists takes no RETURNING clause.

Tests and snapshot changes

• New fixtures: multi/alter_domain_layout.sql (every ALTER DOMAIN subtype, broken and flat) and multi/json_returning.sql (flat and broken RETURNING across the JSON functions). They were committed first with the output from main, so the fix commits show the before/after.
• check_constraint_body* snapshots: only the ALTER DOMAIN statement changes (it is now indented).
• sqljson* and sqljson_queryfuncs* snapshots: changes are whitespace only (I checked this by collapsing whitespace on both sides). A few statements now fit within the line width and collapse onto one line.

Risks

Output changes only. No snapshot has a mid-line double space before a JSON clause keyword any more. Out of scope: when a json_value/json_query call breaks, its clauses are still not indented relative to the opening parenthesis (see the long cases in json_returning).