**Changes**
- Consistent behavior for `!` flag
- The `!` flag used to drop the space when no prefix was added to the output
- This created issues in cases like `f'{Float(123):!.3H}J'` 4
- `!` will now always add a space after the number
- New flag `!!`
- The new flag `!!` operates like `!`, adding a space between the number and the prefix
- `!!` will drop the space if no prefix is added to the number
- See the [documentation](https://prefixed.readthedocs.io/en/stable/format_spec.html#flags) for more information