chore(reactivity): fix typo in dep (#4534) [ci skip]

Author: n2ptune

packages/reactivity/src/dep.ts

@@ -4,7 +4,7 @@ export type Dep = Set<ReactiveEffect> & TrackedMarkers
 
 /**
  * wasTracked and newTracked maintain the status for several levels of effect
- * tracking recursion. One bit per level is used to define wheter the dependency
+ * tracking recursion. One bit per level is used to define whether the dependency
  * was/is tracked.
  */
 type TrackedMarkers = {