test: fix escaping in integration test for control characters

Correctly use backslashes in dedent template literals to expect literal \n and \.
This matches the Ruby code generator's behavior of escaping control characters.

Author: takaokouji

test/integration/ruby-tab/operators.test.js

@@ -105,13 +105,13 @@ describe('Ruby Tab: Operators category blocks', () => {
         const beforeRuby = dedent`
             "\\\\" + "\\\\"
 
-            "\\n" + "\\n"
+            "\\\\n" + "\\\\n"
         `;
 
         const afterRuby = dedent`
             "\\\\" + "\\\\"
 
-            "\\n" + "\\n"
+            "\\\\n" + "\\\\n"
         `;
 
         await clickText('Ruby', '*[@role="tab"]');