show special characters (space, line feed)

[aisbergde]

Using markdown it is imortant to see spaces at end of line because they are part of the Syntax. Also I would like to see if spaces or tabs are used.

Please implement an option to see at least

• space
• tab
• line end

[wbrawner]

Thanks for the feature request! I'll take a look when I have time to do so, or feel free to open a pull request if you're inclined to do so