refs https://github.com/TryGhost/Team/issues/3104
When a post revision author has been deleted, or there is no author
associated with a post revision, the label "Anonymous" is used for the
revision author
We want the diff to be based on what the editor looks like, so we render two
hidden koenig instances and diff the html output, as opposed to using lexical
to render the "frontend" HTML. We also have some weirdness with the last
revision being the same content as the current state of the post. We can look
to fix that at the storage or API level in future
no issue
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### <samp>🤖 Generated by Copilot at 2839ca2</samp>
This pull request adds a feature to show the HTML diff of the post
content changes in the post history modal. It uses the `node-htmldiff`
module to generate the diff and updates the `modal-post-history`
component and its template and style files.
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Co-authored-by: Fabien "egg" O'Carroll <fabien@allou.is>
