Change code actions to provide functionality through `SyntaxRefactoringCodeActionProvider`

Currently, many of the code actions in `SwiftLanguageService/CodeActions` directly conform to `SyntaxCodeActionProvider`. For those for which it makes sense, I think we could avoid some boilerplate (and add some more structure) by making the code action conform to `SyntaxRefactoringCodeActionProvider` as well as `SyntaxRefactoringCodeActionProvider`, removing the explicit implementation of `codeActions(in:)` and instead rely on the synthesized version. As this is a learning-oriented task, please don’t address this purely by using an AI tool, as described in https://github.com/swiftlang/project-operations/blob/main/contributing/ai-tools.md#learning-oriented-contributions.