🐛 Mending Halation is not implemented

[WinterSolstice8]

I affirm:

• I understand that if I do not agree to the following points by completing the checkboxes my issue will be ignored.
• I have read and understood the Contributing Guide and the Code of Conduct.
• I have searched existing issues to see if the issue has already been opened, and I have checked the commit log to see if the issue has been resolved since my server was last updated.

OS / platform the server is running (if known)

Branch affected by issue

base

Steps to reproduce

Mending Halation is not implemented

Expected behavior

Mending Halation is implemented,
see https://wiki.ffo.jp/html/28983.html for a clearer formula than BG wiki