Fix typo and broken link in synchronous runloop documentation

Bug: None
Change-Id: I4162ef32a633124905a9ee8e1713d42c044c3654
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2366798Reviewed-by: Gyuyoung Kim <gyuyoung@igalia.com>
Commit-Queue: Frédéric Wang <fwang@igalia.com>
Cr-Commit-Position: refs/heads/master@{#800510}

docs/patterns/synchronous-runloop.md

@@ -133,7 +133,7 @@ notification or callback being fired) vs waiting for a *state* (such as a
 property on a given object).
 
 When waiting for events, it is crucial that the observer is constructed in time
-to see the event (see also [waiting to late](#starting-waiting-too-late)).
+to see the event (see also [waiting too late](#starting-to-wait-for-an-event-too-late)).
 States, on the other hand, can be queried beforehand in the body of a
 Wait()-style function.