Adjust relative imports in TypeScript when using copy-paste

When copying an import from a file, it would be nice if pasting it in another file would adjust the path

Copying the import from src/folder1/a.ts:

//@filename: src/folder1/a.ts
import { x } from './b';

It would be very useful if pasting it in src/folder2/a.ts would generate (note how the import path was correctly adjusted):

//@filename: src/folder2/a.ts
import { x } from '../folder1/b';

This will be very useful once we switch to relative imports starting from tomorrow.