Short_name: use same value for all truncate maxvalue

[Rushaway]

Description

Use the same max value for truncate short_name like in page.home.php#L42

Motivation and Context

Fix: https://github.com/sbpp/sourcebans-pp/issues/909

How Has This Been Tested?

• Ban someone
• Edit the ban with one of these name (work with all nickname with special chars or emoji)
• Bug triggered :

Screenshots (if appropriate):

Default theme: Custom theme:

Types of changes

• [X] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [X] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [X] I have updated the documentation accordingly.
• [X] I have read the CONTRIBUTING document.