[psteinroe]

Stacked on #995.

Three mechanical changes that the rest of the stack builds on. No output changes: every snapshot stays as it is.

What changed

• GroupKind is gone. Every group_start took a kind, generated from the parser's node list, but the renderer never read it. LayoutEvent::GroupStart carries nothing now, emit_parenthesized_condition no longer takes a kind, and the group_kind macro is removed from pgls_pretty_print_codegen.
• The emitter comes first everywhere. emit_node, emit_node_enum, emit_node_with, the list callbacks and the few private helpers that took (node, e) now take (e, node), like every emit_<node> already did. Closures passed to list helpers are |e, node|, and where a closure only forwarded to a function, the function is passed directly.
• Variants take an enum instead of a bool:
  • case_expr: BranchPlacement::{Aligned, Indented} replaces align: bool.
  • range_var: Only::{Allowed, Omitted} replaces allow_only: bool.
  • alter_table_cmd: emit_alter_table_cmd_of(e, cmd, ObjectType) replaces for_type: bool, so ALTER TABLE passes its own object type.
  • object_with_args: ObjectArguments::{Signature, AggregateSignature, Omitted} replaces two bools and the emit_object_name_only / emit_object_with_args_for_aggregate wrappers.
  • json_value_expr: Prefix::{Space, None} replaces prefix_space: bool.
  • select_stmt: the set operation check takes the OperandSide from utils/predicates.rs instead of is_left_operand: bool.

The bools left in parameters carry state rather than pick a variant: whether something was already written (emitted_any, has_content, first), whether a row is followed by a comma, and whether a space precedes ENCODING.

Tests

• cargo test -p pgls_pretty_print: no snapshot changes.
• cargo test -p pgls_pretty_print --release --test option_matrix -- --ignored
• cargo clippy --workspace --all-targets -- -D warnings