When previewing the rendering of wiki markup while editing, the styling does not match the rendered mode.

This most notably affects:

1. Headings
2. Unordered lists

When fixing this please don't just limit it to the above items, make it work correctly for all the styles.

The fix appears to be quite simple:

Delete most of the div.wiki-edit styles in includes/jira/wikipreview/wiki-renderer.less.