docs: clarify that all elements in an outroing block remain until the transition finishes (#4684)

site/content/docs/02-template-syntax.md

@@ -816,7 +816,7 @@ transition = (node: HTMLElement, params: any) => {
 
 A transition is triggered by an element entering or leaving the DOM as a result of a state change.
 
-When a block is transitioning out, elements inside the block are kept in the DOM until all current transitions have completed.
+When a block is transitioning out, all elements inside the block, including those that do not have their own transitions, are kept in the DOM until every transition in the block has completed.
 
 The `transition:` directive indicates a *bidirectional* transition, which means it can be smoothly reversed while the transition is in progress.