Fixes #55718

Part of #62110

Use the more generic name as suggested in https://github.com/Dart-Code/Dart-Code/issues/1393. This makes the intent of the field more clear and also allows us to extend the concept of preferred code actions to refactorings and other classes of code actions

Experimentally also allows a `preferred` value for `apply` when configuring code aciton keyboard shortcuts. This applies the preferred code action returned from the list of code actions returned

Part of #62110

- Adds a new field `canAutoApply` to code actions. This field indicates that a code action can be applied without additional user input. For quick fixes, this should be set if the fix properly addresses the error

- Enable auto fixes for TS spelling errors

- Added a `editor.action.autoFix` command to triggers auto fixes at the current cursor position

Use `Array<T | U>` when dealing with union types instead of  `(T | U)[]`

Fixes #64390