fix(prettier): kill opinionated prettier_options

Prettier has its own defaults which can be overridden by user's
.prettierrc and project-local package.json as well. Don't impose a new
and conflicting set of defaults in vim-codefmt.

Author: agriffis

instant/flags.vim

@@ -111,9 +111,7 @@ call s:plugin.Flag('shfmt_executable', 'shfmt')
 ""
 " Command line arguments to feed prettier. Either a list or callable that
 " takes no args and returns a list with command line arguments.
-call s:plugin.Flag('prettier_options', [
-    \ '--single-quote', '--trailing-comma=all',
-    \ '--arrow-parens=always', '--print-width=80'])
+call s:plugin.Flag('prettier_options', [])
 
 ""
 " The path to the prettier executable.