Incorrect formatting of code blocks that look like member links

[bioball]

When processing member links in doc comments, things inside code blocks also get formatted, which is incorrect.

This doc comment:

This is foo
```
bar = (foo) { [baz] = 1 }
```

Gets turned into:

This is foo
```
bar = (foo) { `baz` = 1 }
```

To fix this, we maybe should introduce a markdown parser.