This rule is triggered when blockquotes have more than one space after the
blockquote (`>`) symbol:

```markdown
>  This is a blockquote with bad indentation
>  there should only be one.
```

To fix, remove any extraneous space:

```markdown
> This is a blockquote with correct
> indentation.
```

Inferring intended list indentation within a blockquote can be challenging;
setting the `list_items` parameter to `false` disables this rule for ordered
and unordered list items.

Rationale: Consistent formatting makes it easier to understand a document.