fix(js-beautify): Use correct type for json filetype.

Fixes #95.

Author: bjagg

autoload/codefmt/jsbeautify.vim

@@ -41,7 +41,7 @@ function! codefmt#jsbeautify#GetFormatter() abort
   " @throws ShellError
   function l:formatter.FormatRange(startline, endline) abort
     let l:cmd = [s:plugin.Flag('js_beautify_executable'), '-f', '-']
-    if &filetype is# 'javascript'
+    if &filetype is# 'javascript' || &filetype is# 'json'
       let l:cmd = l:cmd + ['--type', 'js']
     elseif &filetype != ""
       let l:cmd = l:cmd + ['--type', &filetype]