fix md viewer line breaks when copying

-set white-space to normal to remove extra space between lines

Author: LeoLamCY

browser/components/MarkdownPreview.js

@@ -73,6 +73,10 @@ h2 {
   padding-bottom: 0.2em;
   margin: 1em 0 0.37em;
 }
+
+body p {
+  white-space: normal;
+}
 `
 }
 

browser/lib/markdown.js

@@ -19,6 +19,7 @@ var md = markdownit({
   linkify: true,
   html: true,
   xhtmlOut: true,
+  breaks: true,
   highlight: function (str, lang) {
     if (lang === 'flowchart') {
       return `<pre class="flowchart">${str}</pre>`