Group @testable imports at the bottom, per public/rules-swift's swiftformat. A
behavior-preserving import-ordering reformat across 252 files (mostly tests).
--trailingclosures was deliberately not adopted (cosmetic, and swiftformat flags
it as caution-worthy).
A simple type that declares no `final` of its own takes the schema's
`finalDefault` as its `{final}` property (XSD 1.0 Schemas section 3.14.2). The
list and union derivation checks read the `final` attribute directly but
ignored `finalDefault`, so `finalDefault="list"` or `"union"` did not block a
list item type or union member type and the schema was wrongly accepted.
The final map now falls back to `finalDefault` for a type without its own
`final`; an explicit `final=""` still overrides the default back to no
restriction, and a built-in item or member type stays unaffected (it is matched
only when the reference resolves to the schema's own namespace).
Caught two invalid schemas: XSTS invalid-schemas-accepted 217 -> 215, no other
bucket moved.
A simple type whose final contains list (or #all) may not be a list itemType,
and one whose final contains union (or #all) may not be a union memberType.
finalRespected already covered restriction and extension; the list and union
directions were unchecked because the derivation-method set does not model
final="list"/"union", so the final attribute is read directly. The itemType /
memberTypes reference is matched only when it resolves to the schema's own target
namespace, so a list or union of a built-in (whose final is empty) is not
confused with a user type of the same local name. Checked for a self-contained
schema.
XSTS: invalid schemas accepted 413 to 411, no other bucket raised.
