Wrap code lines in rendered Editor content

static/markdown.css

@@ -2,6 +2,8 @@ pre {
   background-color: #f5f5f5;
   padding: 0.5rem 0.25rem;
   border-radius: 0.25rem;
+  white-space: pre-wrap;
+  overflow-wrap: break-word;
 }
 table {
   border-collapse: collapse;