bug_report.md: remove confusing 'maintainer information' section (#120711)

When I started out, I was confused by this section and no idea what to put in
and I don't think I'm the only one as I rarely see it filled out.

This means there isn't much usefulness in it for bot processing either; better
just remove it.

.github/ISSUE_TEMPLATE/bug_report.md

@@ -38,11 +38,3 @@ Please run `nix-shell -p nix-info --run "nix-info -m"` and paste the result.
 [user@system:~]$ nix-shell -p nix-info --run "nix-info -m"
 output here
 ```
-
-Maintainer information:
-```yaml
-# a list of nixpkgs attributes affected by the problem
-attribute:
-# a list of nixos modules affected by the problem
-module:
-```