fix: update debounce example to prevent timer leaks in doc tests

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Co-Authored-By: Claude <[email protected]>

Author: lambdalisue

denops/fall/lib/debounce.ts

@@ -15,19 +15,28 @@ export type DebounceOptions = {
  *
  * @example
  * ```ts
- * const debouncedSave = debounce(() => saveData(), { delay: 1000 });
+ * import { debounce } from "./debounce.ts";
+ * import { delay } from "jsr:@std/async@^1.0.0/delay";
+ * 
+ * const saveData = () => console.log("Saving data...");
+ * const debouncedSave = debounce(() => saveData(), { delay: 100 });
  *
- * // Multiple calls within 1000ms will only trigger one save
+ * // Multiple calls within 100ms will only trigger one save
  * debouncedSave();
  * debouncedSave();
  * debouncedSave();
+ * 
+ * // Wait for the debounced function to execute
+ * await delay(150);
  *
  * // Cancel via AbortSignal
+ * const doWork = () => console.log("Doing work...");
  * const controller = new AbortController();
  * const debouncedFunc = debounce(() => doWork(), {
- *   delay: 500,
+ *   delay: 50,
  *   signal: controller.signal
  * });
+ * debouncedFunc();
  * controller.abort(); // Cancels any pending execution
  * ```
  */