add mkdocs documents

docs/test.md

@@ -0,0 +1,25 @@
+# 测试文档
+
+## 测试锚点1
+
+哈哈哈哈哈
+
+## 测试锚点2
+
+哦吼
+
+## 测试代码段
+```php
+if(true) {
+    return "hahah";
+}
+```
+
+## 测试 MkDocs
+!!! warning "Theme extension prerequisites"
+
+    As the `custom_dir` variable is used for the theme extension process,
+    Material for MkDocs needs to be installed via `pip` and referenced with the
+    `name` parameter in `mkdocs.yml`. It will not work when cloning from `git`.
+
+哦豁