docs: Fix invalid json in the mcp example config (#645)

packages/web/src/content/docs/docs/mcp-servers.mdx

@@ -30,6 +30,7 @@ Add a local MCP servers under `mcp.localmcp`.
       "enabled": true,
       "environment": {
         "MY_ENV_VAR": "my_env_var_value"
+      }
     }
   }
 }