Perform trim() on the text after it has been modified (#13)

[mahovich]

Perform a trim() on the text after deleting a chunk from it.

This solves issue #13.

If you don't clear the text in this example:

import { EdgeTTS } from 'edge-tts-universal';
import fs from 'fs/promises';

const text = 'The next paragraph is longer than 4096 characters.\n' + 'Lorem Ipsum. '.repeat(320);

const tts = new EdgeTTS(text);
const result = await tts.synthesize();
const audioBuffer = Buffer.from(await result.audio.arrayBuffer());
await fs.writeFile('output.mp3', audioBuffer);

then after changing the text, an error occurs where the next chunk size is 0, and further processing is interrupted.