feat: add build:test script and improve documentation code blocks

- Added a new script `build:test` to generate test cases from documentation code examples.
- Enhanced documentation files by ensuring proper code block formatting and adding missing closing backticks.
- Updated various markdown files to include new code blocks and fixed formatting issues.

packages/artplayer-vitepress/docs/en/advanced/event.md

@@ -263,6 +263,8 @@ art.on('error', (error, reconnectTime) => {
     console.info(error, reconnectTime);
 });
 
+```
+
 ## `hover`
 
 Triggered when the mouse enters or leaves the player
@@ -521,6 +523,8 @@ art.on('pip', (state) => {
     console.info('pip', state);
 });
 
+```
+
 ## `screenshot`
 
 Triggered when the player captures a screenshot
@@ -774,6 +778,8 @@ art.on('setting', (state) => {
     console.log(state);
 });
 
+```
+
 ## `muted`
 
 Triggered when the mute state changes