Auto merge of #12368 - MovingtoMars:task_name, r=KiChjang

Implement Runnable trait name method for FireSimpleEventTask

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Implement Runnable trait name method for FireSimpleEventTask in `components/script/dom/htmlmediaelement.rs`.

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- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #12346

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- [x] These changes do not require tests because trivial change

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components/script/dom/htmlmediaelement.rs

@@ -738,6 +738,8 @@ impl FireSimpleEventTask {
 }
 
 impl Runnable for FireSimpleEventTask {
+    fn name(&self) -> &'static str { "FireSimpleEventTask" }
+
     fn handler(self: Box<FireSimpleEventTask>) {
         let elem = self.elem.root();
         elem.fire_simple_event(self.type_);