Error reporting enabled warning output is HTML encoded

Problem/Motivation

If you enable "All messages, with backtrace information" under Administration > Configuration > Development > Logging and errors (/admin/config/development/logging) the resulting warning under Administration > Reports > Production check (/admin/reports/prod-check) output is HTML escaped, so that the HTML tags from src/Plugin/ProdCheck/Settings/ErrorReporting.php are shown, not rendered (wrapped in code tag, so as not to render it):

Display all messages, plus backtrace information
Your <a href="https://drupal10.lndo.site/admin/config/development/logging?destination=/admin/reports/prod-check" title="Error reporting">Error reporting</a> settings are set to "Display all messages, plus backtrace information". Are you sure this is what you want and did not mean to use "Display no errors"?

The source:

<td>
Display all messages, plus backtrace information
<div class="description">
Your <em class="placeholder">&lt;a href="https://drupal10.lndo.site/admin/config/development/logging?destination=/admin/reports/prod-check" title="Error reporting"&gt;Error reporting&lt;/a&gt;</em> settings are set to "Display all messages, plus backtrace information". Are you sure this is what you want and did not mean to use "Display no errors"?
</div></td>

The same is true for "User registration" warning from src/Plugin/ProdCheck/Settings/UserRegister.php, if you relax the registration settings.

Steps to reproduce

1. Enable "All messages, with backtrace information" under Administration > Configuration > Development > Logging and errors (/admin/config/development/logging) or relax the "User registration" settings
2. See the resulting warning under Administration > Reports > Production check (/admin/reports/prod-check) output is HTML escaped, so that the HTML tags are shown, not rendered

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes