Heading anchor links open in a new tab when heading contains CJK languages
### Summary
When a Markdown heading contains non-ASCII characters (e.g. Japanese, Chinese, Korean),
clicking its anchor link opens a new tab instead of navigating within the same page:
{width=671 height=450}
### Steps to reproduce
1. Write a heading containing non-ASCII characters in Markdown
1. Click the anchor icon to the right of the heading:
#### Reproduction Heading - 再現用の見出しです
### What is the current *bug* behavior?
`target="_blank"` and `rel="nofollow noreferrer noopener"` are incorrectly applied:
```html
<a href="#reproduction-heading---再現用の見出しです" class="anchor"
rel="nofollow noreferrer noopener" target="_blank"></a>
```
{width=791 height=79}
### What is the expected *correct* behavior?
`target="_blank"` should not be present.
This is a same-page anchor link, just like headings with ASCII-only text:
```html
<a href="#reproduction-heading---再現用の見出しです" class="anchor"></a>
```
{width=472 height=78}
### Output of checks
This bug happens on GitLab.com
issue