[Placeholder] types: `andThen`

### Which function does need to have its types refine/fix?
`andThen`

### What is the problem you faced with current types?
A clear and concise description of problem along with an example code.

### Expected behavior
A clear and concise description of what you expected to happen along with an example code.

### Versions (please complete the following information):

- Deno:
- Fae:
