流程图测试

修好了流程图的渲染，现在支持mermaid和flowchart等主流流程图的渲染了

mermaid流程图

sequenceDiagram
    loop Daily query
        Alice->>Bob: Hello Bob, how are you?
        alt is sick
            Bob->>Alice: Not so good :(
        else is well
            Bob->>Alice: Feeling fresh like a daisy
        end

        opt Extra response
            Bob->>Alice: Thanks for asking
        end
    end

graph TD
    B((开始)) -->C{判断}
    C --  a=1 -->D[执行语句1]
    C --  a=2  -->E[执行语句2]
    C --  a=3 -->F[执行语句3]
    C -- a=4  -->G[执行语句4]
    D--> AA((结束))
    E--> AA
    F--> AA
   G--> AA

graph TD;
    A-->B;
    A-->C;
    B-->D;
    C-->D;

flowchart流程图