update cherry-markdown and update editormd code block style (#888)

* fix: first open document, cherryMarkdown not have theme

* fix: modify prismjs style and improve image clarity

* update cherry-markdown

* optimiztion: cherry-markdown

* feat: cherry-markdown add auto-save and update icon

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Co-authored-by: zhangsheng.93 <zhangsheng.93@bytedance.com>

static/cherry/drawio-demo.js

@@ -53,7 +53,7 @@ function addPostMessageListener(graphEditor) {
       case 'getData':
         editorUIInstance.editor.graph.stopEditing();
         var xmlData = mxUtils.getXml(editorUIInstance.editor.getGraphXml());
-        editorUIInstance.exportImage(1, "#ffffff", true, null, true, 50, null, "png", function (base64, filename) {
+        editorUIInstance.exportImage(2, "#ffffff", true, null, true, 50, null, "png", function (base64, filename) {
           window.parent.postMessage({
             mceAction: 'getData:success',
             eventName: 'getData:success',