* rdar://105027055: Do not use as-casts in specializations.
Introduce _specializingCast and use it instead of `as?`-casts inside
if ladders that implement generic specialization.
`as?` invokes undesirable runtime machinery such as bridging checks.
* rdar://105027055: Ensure AttributedString views have properly aligned bounds
* rdar://105027055: Implement index(_:offsetBy:limitedBy:) in AttributedString views
We have agreed that `agreeWithArgument` sounds more intuitive to localizers than
`agreeWithReplacement`. This attribute hasn't been adopted internally yet, so we
can afford to rename it just before the SDK freeze.
* (101354563) Separate CodableWithConfiguration into standalone file
* (101354563) Update PredicateExpression archive formats
* (101354563) Codable Support for Predicate
* (101354563) Assert on unsupported keypaths
* rdar://107778676 Stop vendoring the Collections package
* rdar://107778676 Fix test expectation
AttributedString.CharacterView needs to round all indices down to the
nearest Character boundary to avoid semantic issues with its
Collection conformance. This means that CharacterView slices can never
start or end in between Character boundaries.
* Remove a stray print statement
