Fix accumulating indentation in CREATE TABLE columns - #906

CREATE TABLE columns with constraints such as NOT NULL can be split into several IdentifierList groups. Reindent currently anchors each group to its constraint, so each following column moves farther to the right. Anchor these lists to the column-definition parenthesis instead.

The change is limited to space-based column alignment in CREATE TABLE; indent_columns, tab indentation, nested function arguments, and CREATE TABLE AS retain their existing behavior. Tests cover several constraints, formatting twice, CTAS, and a following SELECT statement.

Fixes #688.

• ran the tests (pytest): 512 passed, 2 xfailed, 1 xpassed on Linux Python 3.13
• all style issues addressed (ruff)
• changes are covered by tests (5 regression cases fail on the unchanged base)
• documentation checked; no public API changes

The original issue SQL, including its primary key, formats consistently. The reindent scaling benchmark passes for both the base and this change.