chore: fix a typo in startTransition docs (#7361)

src/content/reference/react/startTransition.md

@@ -53,7 +53,7 @@ function TabContainer() {
 
 * You can wrap an update into a Transition only if you have access to the `set` function of that state. If you want to start a Transition in response to some prop or a custom Hook return value, try [`useDeferredValue`](/reference/react/useDeferredValue) instead.
 
-* The function you pass to the of `startTransition` is called immediately, marking all state updates that happen while it executes as Transitions. If you try to perform state updates in a `setTimeout`, for example, they won't be marked as Transitions.
+* The function you pass to `startTransition` is called immediately, marking all state updates that happen while it executes as Transitions. If you try to perform state updates in a `setTimeout`, for example, they won't be marked as Transitions.
 
 * You must wrap any state updates after any async requests in another `startTransition` to mark them as Transitions. This is a known limitation that we will fix in the future (see [Troubleshooting](/reference/react/useTransition#react-doesnt-treat-my-state-update-after-await-as-a-transition)).