Remove a stray throws in the declaration of __requiringUnsafe(). (#1340)

This function is not meant to handle `try`, just `unsafe`.

### Checklist:

- [x] Code and documentation should follow the style of the [Style
Guide](https://github.com/apple/swift-testing/blob/main/Documentation/StyleGuide.md).
- [x] If public symbols are renamed or modified, DocC references should
be updated.

Author: grynspan

Sources/Testing/Test+Macro.swift

@@ -556,7 +556,7 @@ extension Test {
 ///
 /// - Warning: This function is used to implement the `@Test` macro. Do not use
 ///   it directly.
-@unsafe @inlinable public func __requiringUnsafe<T>(_ value: consuming T) throws -> T where T: ~Copyable {
+@unsafe @inlinable public func __requiringUnsafe<T>(_ value: consuming T) -> T where T: ~Copyable {
   value
 }