Language-specific completion for markdown fenced code blocks.
Completion will be enabled for the languages specified in
g:markdown_fenced_languages
if using tpope's vim-markdown plugin, or
g:vim_markdown_fenced_languages
if using plasticboy's vim-markdown.
Defaults to ['markdown'].
A list of filetypes that the plugin should work for. This is useful if you have
files that have an e.g. vimwiki.markdown filetype.