chore: 采纳一些clippy的建议

src-tauri/src/downloader/tasks/audio_task.rs

@@ -371,7 +371,7 @@ impl AudioTask {
                 download_task: download_task.clone(),
                 start,
                 end,
-                url: audio_task.url.to_string(),
+                url: audio_task.url.clone(),
                 file: file.clone(),
                 chunk_index,
             };

src-tauri/src/downloader/tasks/danmaku_task.rs

@@ -81,7 +81,7 @@ impl DanmakuTask {
             let config = download_task.app.get_config().read().danmaku_config.clone();
             let ass_file = File::create(&ass_path)
                 .context(format!("创建弹幕ASS文件`{}`失败", ass_path.display()))?;
-            let title = filename.to_string();
+            let title = filename.clone();
             xml_to_ass(&xml, ass_file, title, config).context("将弹幕XML转换为ASS失败")?;
         }
 

src-tauri/src/downloader/tasks/video_task.rs

@@ -382,7 +382,7 @@ impl VideoTask {
                 download_task: download_task.clone(),
                 start,
                 end,
-                url: video_task.url.to_string(),
+                url: video_task.url.clone(),
                 file: file.clone(),
                 chunk_index: i,
             };