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).
The compact-syntax parser now skips [ ... ] documentation/grammar
annotations (balanced over nesting) wherever they may appear, before a
define or before a pattern, and treats div { ... } as transparent
grammar grouping that contributes its defines and start directly. A
define literally named div still parses when assigned. Splits the
name-class and token helpers into a companion file to stay within the
type and file length budget.
