Clarify ControlFlow::Poll doc for web
Make it clear that ControlFlow::Poll causing events to be sent on
`requestAnimationFrame` is an implementation detail which should not be
relied on.
@@ -74,9 +74,11 @@ pub enum ControlFlow {
/// When the current loop iteration finishes, immediately begin a new iteration regardless of
/// whether or not new events are available to process.
///
- /// For web, events are queued and usually sent when `requestAnimationFrame` fires but sometimes
+ /// ## Platform-specific
+ /// - **Web:** Events are queued and usually sent when `requestAnimationFrame` fires but sometimes
/// the events in the queue may be sent before the next `requestAnimationFrame` callback, for
- /// example when the scaling of the page has changed.
+ /// example when the scaling of the page has changed. This should be treated as an implementation
+ /// detail which should not be relied on.
Poll,
/// When the current loop iteration finishes, suspend the thread until another event arrives.
Wait,
