chore: replace some type casts and fix variable and filename typos (#93)

packages/runtime-core/src/componentProxy.ts

@@ -2,7 +2,7 @@ import { ComponentInternalInstance, Data } from './component'
 import { nextTick } from './scheduler'
 import { instanceWatch } from './apiWatch'
 import { EMPTY_OBJ, hasOwn, globalsWhitelist } from '@vue/shared'
-import { ExtracComputedReturns } from './apiOptions'
+import { ExtractComputedReturns } from './apiOptions'
 import { UnwrapRef } from '@vue/reactivity'
 
 // public properties exposed on the proxy, which is used as the render context
@@ -26,7 +26,7 @@ export type ComponentPublicInstance<
 } & P &
   UnwrapRef<B> &
   D &
-  ExtracComputedReturns<C> &
+  ExtractComputedReturns<C> &
   M
 
 export const PublicInstanceProxyHandlers = {