docs: update basic usages

Author: farnabaz

docs/content/3.rendering/1.vue.md

@@ -22,6 +22,7 @@ The `MDC` component is the simplest way to render markdown. Pass markdown conten
 ```vue
 <script setup>
 import { MDC } from 'mdc-syntax/vue'
+import Alert from './Alert.vue'
 
 const content = `# Hello World
 
@@ -34,7 +35,7 @@ This is an alert!
 </script>
 
 <template>
-  <MDC :markdown="content" />
+  <MDC :markdown="content" :components="{ Alert }" />
 </template>
 ```
 

docs/content/3.rendering/2.react.md

@@ -25,6 +25,7 @@ The `MDC` component is the simplest way to render markdown. Pass markdown conten
 
 ```tsx
 import { MDC } from 'mdc-syntax/react'
+import Alert from './Alert.tsx'
 
 const content = `# Hello World
 
@@ -36,7 +37,7 @@ This is an alert!
 `
 
 export default function App() {
-  return <MDC markdown={content} />
+  return <MDC markdown={content} component={{ Alert }} />
 }
 ```