checkbox to align separators by inserting space

**Is your feature request related to a problem? Please describe.**
There is no way to cause this
- `[abc]`
- `[defghi]`
to be aligned as
- `[abc   ]`
- `[defghi]`

**Describe the solution you'd like**
up to you. Checkbox?

**Describe alternatives you've considered**
none
