fix: added a tab spacing to the docs file

Author: AndreaPontrandolfo

docs/rules/ensure-matching-remove-event-listener.md

@@ -33,7 +33,7 @@ Examples of **correct** code for this rule:
 useEffect(() => {
     window.addEventListener("keydown", handleUserKeyPress);
     return () => {
-    window.removeEventListener("keydown", handleUserKeyPress);
+        window.removeEventListener("keydown", handleUserKeyPress);
     };
 }, []);
 ```