Ayooluwa Isaiah

## Problems summary When I run `:CocCommand fzf-preview.Ctags`, I get this message: ``` [coc.nvim]: Error on notification "runCommand": request error nvim_call_function - Set excmd=number or excmd=combine in universal-ctags options ```...

I described the reasoning behind the use of `safeHTMLAttr` in a clearer way by explaining the presence of `ZgotmplZ` in the first sample.

I was looking for a way to test for the presence of an optional shortcode parameter, but didn't find helpful information in the docs. This PR documents how the it...

Should fix #210

Right now you can only add images to a slide. I think it should be possible to set an image as the slide background too