新加Support，Documentation下载文档

src/components/common/Aside.vue

@@ -37,7 +37,11 @@
             <Support />
             <span>Support</span>
           </template>
-          <el-menu-item index="4-1">Documentation</el-menu-item>
+          <el-menu-item>
+            <a href="/download/ComPDFKit-SaaS-API.md" download="compdfkit-saas-api.md" style="color:rgb(102, 102, 102)">
+              Documentation
+            </a>
+          </el-menu-item>
         </el-submenu>
       </el-menu>
     </div>
@@ -60,7 +64,11 @@
       </el-submenu>
       <el-submenu index="4">
         <template slot="title"><span>Support</span></template>
-        <el-menu-item index="4-1">Documentation</el-menu-item>
+        <el-menu-item>
+            <a href="/download/ComPDFKit-SaaS-API.md" download="compdfkit-saas-api.md" style="color:rgb(102, 102, 102)">
+              Documentation
+            </a>
+          </el-menu-item>
       </el-submenu>
     </el-menu>
   </div>