**How to reproduce** :
* Go to any page that uses Language Converters' `-{T|}` syntax to change title, Such as [this](https://zh.wikipedia.org/w/index.php?variant=zh-cn&oldid=68234793)
**What happens?**:
Raw HTML tag can be seen in the Title
**What should have happened instead?**:
Title should by styled by the html in the title
**Whats the reason behind it**:
Currently, you can put whatever you want in Language Converters' `-{T|}` syntax including HTML syntax like magic word `displaytitle` without using `displaytitle` function in CoreParserFunctions.php.
When we need to process the title, the logic in Parser.php will call `getTargetLanguageConverter()->getConvRuleTitle()` and then using the string from convertTitle and set it as the new title using `setTitleText`. You can see the logic [here](https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/core/+/95af3986a1b3b3aabd6f0bb21161a182f7578a62/includes/parser/Parser.php#700).
However, due to the changes made in T291985, the string from convertTitle will pass through `htmlspecialchars` before setting as the new title, which causes display issue like [this](https://zh.wikipedia.org/w/index.php?oldid=68234793) when we do not want them to be converted by `htmlspecialchars`.
**Potential Solution**:
One solution can be to convert title from `getTargetLanguageConverter()->getConvRuleTitle()` using `displaytitle` function in CoreParserFunctions.php, with adding benefits such as HTML sanitization.