This show various styles for our diff action, the background being hardcoded to gray (`#C0C0C0`) The reference style sheet is:

`resources/mediawiki.action/mediawiki.action.history.diff.css`.

This file might help us fix our diff colors which have been a recurring issues among the community for a loooong time.

First, show the diff mostly like it would be chown on a wiki

- | Some content deleted / replaced | + | Some content added / replacement

Below are some basic lines being applied one or two classes. Mainly for debugging purposes

Diff
`diff-addedline`: added line
`diff-deletedline`: deleted line
`diff-context`: context
Same as above with a `<span>` child element having the `diffchange` class
Diffchange
Added line + diffchange
Deleted line + diffchange
Context + diffchange