Highlight edit changes

[Mattis142]

When looking at the edit history edited characters should be highlighted, if a post is especially long it'd be useful to see which part got changed at first sight, also IF the url of a post has been edited it should be automatically expanded and the modified part should be highlighted too since currently you cannot see if the url got edited or not here:

[Andrewblasco]

I also see this it would be useful. BUT, sometimes the edition is something as simple as change the language selected to label your toot... Maybe it is a difficult issue 🤔

[LucasGGamerM]

Done as of #297