feat(code): add support for code block folding (#259)

exampleSite/config.toml

@@ -678,6 +678,9 @@ enableEmoji = true
       # whether to show the copy button of the code block
       # 是否显示代码块的复制按钮
       copy = true
+      # the maximum number of lines of displayed code by default
+      # 默认展开显示的代码行数
+      maxShownLines = 10
     # KaTeX mathematical formulas config (KaTeX https://katex.org/)
     # KaTeX 数学公式配置 (KaTeX https://katex.org/)
     [params.page.math]