fix: add vs dot unified writing paradigm (vuejs#1999)

Author: zhousg

src/guide/essentials/computed.md

@@ -138,7 +138,7 @@ See also: [Typing Computed](/guide/typescript/composition-api.html#typing-comput
 
 </div>
 
-## Computed Caching vs Methods
+## Computed Caching vs. Methods
 
 You may have noticed we can achieve the same result by invoking a method in the expression:
 

src/guide/essentials/conditional.md

@@ -98,7 +98,7 @@ The difference is that an element with `v-show` will always be rendered and rema
 
 `v-show` doesn't support the `<template>` element, nor does it work with `v-else`.
 
-## `v-if` vs `v-show`
+## `v-if` vs. `v-show`
 
 `v-if` is "real" conditional rendering because it ensures that event listeners and child components inside the conditional block are properly destroyed and re-created during toggles.