LoroText.update(targetStr) may not capture the edit intent

[zxch3n]

The current .update(targetStr) will calculate the difference based on the Myers diff. Although the computed difference has minimal edits, the difference can be very counterintuitive:

import { expect, it, describe, beforeEach } from 'vitest';
import { LoroDoc } from 'loro-crdt';

it('sync', () => {
  const docA = new LoroDoc();
  const docB = new LoroDoc();
  docA.setPeerId(1);
  docB.setPeerId(0);
  docA.getText('text').update('Hello');
  docB.import(
    docA.export({
      mode: 'update',
    })
  );

  const textA = docA.getText('text');
  textA.update('Oh, Hello World!\nThis sentence should stay untouched!');

  const textB = docB.getText('text');
  textB.update('Hmmm, Hello Alice!');

  docA.import(docB.export({ mode: 'update' }));
  docB.import(docA.export({ mode: 'update' }));
  console.dir(docA.exportJsonUpdates(), { depth: 100 });

  expect(docA.getText('text').toString()).toBe(
    'Oh, Hmmm, Hello World! Alice!\nThis sentence should stay untouched!'
  );

  // - Oh, Hmmm, Hello World! Alice!
  // + Oh, Hmmm, Hello World!
  // - This sentence should stay untouched!
  // + This sentence should stay unto Alice!uched!
});

https://stackblitz.com/edit/stackblitz-starters-2lf3ty?file=loro.test.js

The diagram of the cause of the issue: