docs: fix echarts shortcodes error

exampleSite/content/posts/theme-documentation-shortcodes.en.md

@@ -601,7 +601,7 @@ Just insert your ECharts option in `JSON`/`YAML`/`TOML` format in the `echarts`
 Example `echarts` Input in `JSON` format:
 
 ```json
-{{/* echarts */}}
+{{</* echarts */>}}
 {
   "title": {
     "text": "Summary Line Chart",

exampleSite/content/posts/theme-documentation-shortcodes.fr.md

@@ -606,7 +606,7 @@ Just insert your ECharts option in `JSON`/`YAML`/`TOML` format in the `echarts`
 Example `echarts` Input in `JSON` format:
 
 ```json
-{{/* echarts */}}
+{{</* echarts */>}}
 {
   "title": {
     "text": "Summary Line Chart",

exampleSite/content/posts/theme-documentation-shortcodes.zh-cn.md

@@ -603,7 +603,7 @@ ECharts 提供了常规的 [折线图](https://echarts.apache.org/zh/option.html
 一个 `JSON` 格式的 `echarts` 示例:
 
 ```json
-{{/* echarts */}}
+{{</* echarts */>}}
 {
   "title": {
     "text": "折线统计图",