Improve kommentary integration example

Make sure to mention that `auto` should be set when configuring
kommentary. This causes kommentary to use the `commentstring` setting
and not the default ("//" and "/* */").

Documentation improvement from #16

Author: JoosepAlviste

README.md

@@ -203,6 +203,8 @@ its `hook_function` configuration:
 
 ```lua
 require('kommentary.config').configure_language('typescriptreact', {
+  single_line_comment_string = 'auto',
+  multi_line_comment_strings = 'auto',
   hook_function = function()
     require('ts_context_commentstring.internal').update_commentstring()
   end,