docs: fix typescript declare example (#2034)

cinob · web-flow · commit 0b88647eb08d · 2021-10-11T19:21:29.000+09:00
`ComponentCustomProperties` is defined but never used.
diff --git a/docs/guide/typescript-support.md b/docs/guide/typescript-support.md
@@ -12,7 +12,6 @@ To do so, declare custom typings for Vue's `ComponentCustomProperties` by adding
 
 ```ts
 // vuex.d.ts
-import { ComponentCustomProperties } from 'vue'
 import { Store } from 'vuex'
 
 declare module '@vue/runtime-core' {
