add error message

Author: Zettat123

options/locale/locale_en-US.ini

@@ -2152,6 +2152,7 @@ settings.choose_branch = Choose a branch…
 settings.no_protected_branch = There are no protected branches.
 settings.edit_protected_branch = Edit
 settings.protected_branch_required_rule_name = Required rule name
+settings.protected_branch_duplicate_rule_name = Duplicate rule name
 settings.protected_branch_required_approvals_min = Required approvals cannot be negative.
 settings.tags = Tags
 settings.tags.protection = Tag Protection