Highlight fenced languages with abbreviated langauge name

[FernandoBasso]

Thanks a lot for this plugin! Really appreciate it!!

I added this to my init file:

let g:asciidoctor_fenced_languages = ['c', 'ruby', 'typescript']

Then, if I open a source block with the abbreviated (extension-like) language name, highlighting doesn't happen:

[source,rb]
----
xs = [1..3]
xs.each { |n| p n }
----

If I change rb to ruby, then it does work.

The question is, should we expected the first approach to work or it is better to stay with full language names? The help mentions the first option only, so I guess that is the style supported, but though I'd ask just in case.