Fix typography for submission diff

[theskumar]

• The numbers don't break
• make the heading consistent, everything gets a h4
• Update the color and style for added/deleted text

closes #3671

[theskumar]

I've able to get another version of compare view working with rich text display. See some of the screenshots below. If there is enough interest, after we merge this, I'll polish this up a bit and send a pull request. It uses html-diff==0.4.1

The styling is borrowed from the Github's markdown diff preview.

[wes-otf]

Looks/works great! Especially the Proposal Infomation (Old)/(New) is a super useful addition.

[wes-otf]

Two small things after more testing not mentioned in the original issue:

1. Ordered lists get turned to unordered lists and new lines look to be ignored sometimes in Rich Text fields (ie. "Here are some bullets:", "Now for some numbering:" & "Here's a link:").
2. Links & their changes are not shown.

In the following screenshots the Open Tech Fund link was swapped from https://opentech.fund to https://www.opentech.fund but the compare shows this as unchanged.

The application w/ Rich Text & Markdown:

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The compare view:

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[frjo]

@wes-otf Good point on the links, we should add some code to handle them.

The submission contains large amount of HTML due to the RichTextEditor and that many people paste in text straight from Microsoft Word etc. To diff the HTML directly is not workable.

What Hypha instead does is to strip all the HTML and compare that instead. Then the code tries to reassemble the text to show it in some resemblance to the original.

This works but is far from optimal. We just discussed today that it might be worth testing to convert the text to markdown instead and compare that.

[theskumar]

We just discussed today that it might be worth testing to convert the text to markdown instead and compare that.

After the call, I spent some more time with it. See my experiment with diffing the html itself and displaying it to user here #3673 (comment)

If the rich text support is needed, this might be the best way to go.

[wes-otf]

I think that would make a lot of sense. Would definitely be interested in your HTML diff @theskumar. Maybe we could do a beta for something like that similarly to the submission view to gauge interest.