Italic syntax parsing error.

Sample below

```
_abc: This variable is similar with `_bcd`
```

should be rendered as:

_abc: This variable is similar with `_bcd`

But in MacDown, it was rendered as:

_abc: This variable is similar with `_ bcd` (There is no space before "bcd")

Reproduce the fenced sample in MacDown and compare its output with the expected rendering shown in the issue. Trace the Markdown parsing or rendering entry point responsible for the inserted space, then verify that the sample renders exactly as expected.

Written by the indexing model from the issue text.