This treats tabs faked using spaces as if they were real tabs meaning that you can't select the middle of them.

This reverts commit e6519cb820e99c9d4283f395fdee904d6fe4a260.

With the upcoming changes in TypeScript 3.8 to support `import type`, it is even more compelling to declare weak references via types rather than strong references via concrete classes. Most APIs in Monaco already do this well, accepting `monaco.IRange` instead of `monaco.Range`, though `IIdentifiedSingleEditOperation` appears to be an exception in this regard, which means a strong dependency on `monaco.Range` is required to use `ITextModel.pushEditOperations()`.

It would be nice to relax this constraint, though I admit I have not yet attempted to trace through whether this breaks anything since I am submitting this via GitHub's web UI.