Add event link on the nix.ug broken

[NobbZ]

In the upper left there is a link/button to add a new event/UG. This link seems to be broken, as the fragment does not point to the correct heading:

https://github.com/nix-how/nix.ug#adding-a-new-user-group-to-the-list is the current link, while https://github.com/nix-how/nix.ug#adding-a-new-user-group-or-event-to-the-list seems to be the correct target.

-https://github.com/nix-how/nix.ug#adding-a-new-user-group-to-the-list
+https://github.com/nix-how/nix.ug#adding-a-new-user-group-or-event-to-the-list

[MatthewCroughan]

Closed by 6961380