Del button should work the same in Visual & HTML Editors

[aaroncampbell]

If you highlight something in the visual editor and click strikethrough (del) it wraps the content in <del> tags. If you do the same in the HTML editor it gets wrapped in <del> tags with the datetime parameter filled with what looks like an ISO 8601 date.

Example:

<del>Deleted from Visual</del>

<del datetime="2012-03-01T13:56:01+00:00">Deleted from HTML</del>

We should standardize these.

One of the side effects of this is that the del button in the HTML editor can't be used in captions because it messes up the quotes (#18311).

[azaozz]

The same is true for the <ins> tag. The datetime attribute for <del> and <ins> doesn't seem to be displayed or used by the browsers so removing them wouldn't affect anything.

[jane]

Fine with removing the timestamp if it makes things easier. Easy enough to add datetime with a plugin if someone really wants that attribute.

[aaroncampbell]

This patch looks good to go.

[westi]

I think removing the timestamp here is a retrograde move and would rather we didn't regress this.

[nacin]

If captions are breaking we need to fix captions, not this.

[aaroncampbell]

We're going to fix captions instead of regressing here

[mark-k]

IMO this is wrong. Semantically (​http://www.whatwg.org/specs/web-apps/current-work/multipage/edits.html) the del tag have less meaning without the deletion time. I guess it is OK if WordPress do not make it easy to provide the info at all, but to provide it in the less used editor component while ignoring the more used one is strange.

related #23321