Web: queue EventLoopProxy::send_event() to microtask

src/changelog/unreleased.md

@@ -40,6 +40,16 @@ changelog entry.
 
 ## Unreleased
 
+### Changed
+
+- On Web, let events wake up event loop immediately when using
+  `ControlFlow::Poll`.
+
+### Fixed
+
+- On Web, fix `EventLoopProxy::send_event()` triggering event loop immediately
+  when not called from inside the event loop. Now queues a microtask instead.
+
 ### Removed
 
 - Remove `EventLoop::run`.