[6 KYU] Backspaces in string (Solution)

I decided to use typescript.
```ts
export function cleanString(s: string): string {
  let ret: string[] = [];
  
  s.split("").forEach(r => {
    if(r == "#"){
      ret.pop();
    } else ret.push(r);
  })
  
  return ret.join("");
}