feat: add confirmation modal when assigning admin:admins-mods privilege

public/language/en-GB/admin/manage/privileges.json

@@ -44,6 +44,7 @@
 	"admin-settings": "Settings",
 
 	"alert.confirm-moderate": "<strong>Are you sure you wish to grant the moderation privilege to this user group?</strong> This group is public, and any users can join at will.",
+	"alert.confirm-admins-mods": "<strong>Are you sure you wish to grant the &quot;Admins &amp; Mods&quot; privilege to this user/group?</strong> Users with this privilege are able to promote and demote other users into privileged positions, <em>including super administrator</em>",
 	"alert.confirm-save": "Please confirm your intention to save these privileges",
 	"alert.saved": "Privilege changes saved and applied",
 	"alert.confirm-discard": "Are you sure you wish to discard your privilege changes?",

public/src/admin/manage/privileges.js

@@ -50,6 +50,15 @@ define('admin/manage/privileges', [
 							checkboxEl.prop('checked', !checkboxEl.prop('checked'));
 						}
 					});
+				} else if (privilege.endsWith('admin:admins-mods') && state) {
+					bootbox.confirm('[[admin/manage/privileges:alert.confirm-admins-mods]]', function (confirm) {
+						if (confirm) {
+							wrapperEl.attr('data-delta', delta);
+							Privileges.exposeAssumedPrivileges();
+						} else {
+							checkboxEl.prop('checked', !checkboxEl.prop('checked'));
+						}
+					});
 				} else {
 					wrapperEl.attr('data-delta', delta);
 					Privileges.exposeAssumedPrivileges();