Does not work for `$`

I am trying to replace each newline with ``, and to also add `` to the very end. However if it ends with a newline I only want one ``.

I wrote a regular expression for this using $, however this does not seem supported.

Some sample code (TS):
```ts
(async function test() {
console.log('runnig test');
const text = `
first line
second line
third line`.trimStart();
let result = '';
const readStream = Readable
.from(text)
.pipe(replaceStream(/\s*[\n\r]+|$/g, ' '));
const writable = new Writable({
write(chunk: string) {
result += chunk;
}
});

readStream.pipe(writable);
await finished(readStream);

console.log('Done! Result:');
console.log('---')
console.log(result);
console.log('---')
})();
```