fix: pretty sql parsing error messages

Previously when running `pico.sql [[ create table foo ]]` we would get
this output:
```
---
- null
- "sbroad: rule parsing error:  --> 1:9\n  |\n1 |  create table foo \n  |  ^---\n
  \ |\n  = expected Unique"
...
```

But now the output will be:
```
---
- null
- |+
  sbroad: rule parsing error:  --> 1:9
    |
  1 |  create table foo
    |         ^---
    |
    = expected Unique

...
```