feat: rework test report aesthetics

[ivov]

Reworks the lis test report so a run is easier to read at a glance:

  demo
    ├── ✓ slugify lowercases and hyphenates
    ├── ✗ a fallible test that returns Err
    └── translate moves along each axis
        ├── ✓ moves_right
        └── ✓ moves_up

  Failures

  ✗ a fallible test that returns Err · test returned Err
        ╭─[src/calc.test.lis:28:4]
     28 │ fn returns_err() -> Result<(), error> {
        ·    ─────┬─────
        ·         ╰── name is required
        ╰────

  ✗ 1 failed · 3 passed (118ms)