fix: fix code block wrong background in example title

Author: MC-XiaoHei

docs/.vitepress/theme/anchor/exampleAutoAnchorPreprocessor.ts

@@ -17,7 +17,7 @@ export const exampleAutoAnchorPreprocessor = (md: MarkdownIt) => {
  position: relative;
  top: 32px;">
  <TitleAnchor anchor="${processedTitle}">
-    <h3 id="${processedTitle}" style="
+    <h3 id="${processedTitle}" class="example-title-anchor" style="
     -webkit-user-select: none;
     -moz-user-select: none;
     -ms-user-select: none;

docs/.vitepress/theme/style/global.css

@@ -67,4 +67,8 @@ kbd:not(.DocSearch-Button-Key) {
 
 .tip.custom-block > .danger.custom-block {
     background-color: #fde4e8;
+}
+
+.example-title-anchor > code {
+    background-color: rgba(0, 0, 0, 0) !important;
 }