添加mermaid图表接口 (#85)

* 添加mermaid图表接口

* 添加类型文件

* Update package.json

* Create next-env.d.ts

client/src/types/mermaid.d.ts

@@ -0,0 +1,19 @@
+declare module "mermaid" {
+    import mermaidAPI from "mermaid";
+    const mermaid: any;
+    export default mermaid;
+  
+    // 扩展 mermaidAPI
+    interface MermaidAPI extends mermaidAPI.mermaidAPI {
+      contentLoaded: (
+        targetEl: Element,
+        options?: mermaidAPI.mermaidAPI.Config
+      ) => void;
+    }
+  
+    const mermaidAPIInstance: MermaidAPI;
+    export default mermaidAPIInstance;
+  }
+type Dispatch = (action: Action) => void;
+
+