Merge pull request preservim#498 from jrwrigh/master

fixup: Remove debugging echo message

Author: shirosaki

ftplugin/markdown.vim

@@ -789,7 +789,6 @@ function! s:MarkdownHighlightSources(force)
     let filetypes = {}
     for line in getline(1, '$')
         let ft = matchstr(line, '```\s*\zs[0-9A-Za-z_+-]*\ze.*')
-        echom ft
         if !empty(ft) && ft !~ '^\d*$' | let filetypes[ft] = 1 | endif
     endfor
     if !exists('b:mkd_known_filetypes')