Post History

Some codes are not rendered after saving a post while they are rendered in the preview.

When I was writing [this post](https://math.codidact.com/q/278382), I noticed that the color style html codes rendered well in the preview, but after posting, I saw that they were not rendered.

I know that all html codes may not be supported on Codidact; however, I expect that those of them rendered in the preview also can be rendered after saving a post.