Plain text email notification for mentions contains Velocity code

Steps to reproduce:

• Configure email sending. I used https://github.com/rnwood/smtp4dev with the Docker image and configured the port and sender address in the administration.
• Make sure your user account has an email.
• Open the notification settings of your user account and set notifications to hourly
• Log in as another user and add a comment that mentions the user account.
• Go to the scheduler application as admin and trigger the hourly notification sender job.
• Check your emails.

Expected result:

The plain text email contains a nicely readable summary of the mention event.

Actual result:

The plain text version of the email is

Event(s) on the wiki:

-------------------------------------------------------------------------------
org.xwiki.contrib:mentions-notifications:
  [mentions.mention] [Home](http://localhost:8080/xwiki/bin/view/Main/).
  edited by Username.
  2025/07/31 15:16
  Changes: http://localhost:8080/xwiki/bin/view/Main/?viewer=changes&rev1=${origdoc.version}&rev2=${newdoc.version}

The fact that it's a mention isn't clearly mentioned here, there are just some internal strings and additionally this contains Velocity code. "Username" is the actual name of the user that triggered the notification on the main page, so that part is correct.