All content init taking a closure should allow the closure to throw with the init being rethrowing

Everything is in the title.

An example:
```swift
/* Current Division init */
public init(@ContentBuilder<Content> content: () -> [Content]) {
   self.content = content()
}
/* Replacement */
public init(@ContentBuilder<Content> content: () throws -> [Content]) rethrows {
   self.content = try content()
}
```