This rule is triggered when the symbols used in the document for emphasis do not
match the configured emphasis style:

```markdown
*Text*
_Text_
```

To fix this issue, use the configured emphasis style throughout the document:

```markdown
*Text*
*Text*
```

The configured emphasis style can be a specific symbol to use ("asterisk",
"underscore"), or can require that usage be consistent within the document.

Note: Emphasis within a word is restricted to "asterisk" in order to avoid
unwanted emphasis for words containing internal underscores like_this_one.

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