Add interface{} to any replacement to make fmt, exclude *.pb.go (#30461)

Since https://github.com/go-gitea/gitea/pull/25686, a few `interface{}`
have sneaked into the codebase. Add this replacement to `make fmt` to
prevent this from happening again.

Ideally a linter would do this, but I haven't found any suitable.

.gitattributes

@@ -1,5 +1,6 @@
 * text=auto eol=lf
 *.tmpl linguist-language=Handlebars
+*.pb.go linguist-generated
 /assets/*.json linguist-generated
 /public/assets/img/svg/*.svg linguist-generated
 /templates/swagger/v1_json.tmpl linguist-generated