v6: odd semantics for using a different "noExt" loader

[boneskull]

I want to use the JS loader for files without extension.

Before v6:

import cosmiconfig from 'cosmiconfig';

cosmiconfig(namespace, {
  loaders: {
    noExt: cosmiconfig.loadJs
  }
});

After:

import {cosmiconfig, defaultLoaders} from 'cosmiconfig';

cosmiconfig(namespace, {
  loaders: {
    noExt: defaultLoaders['.js']
  }
});

1. Because I am not looking to implement my own loader, I need to dig into the defaultLoaders object to get at function I need. It's buried pretty deep in there.
2. Having to use bracket notation to reference the function is also less-than-ideal

I'm not sure what the impetus was behind changing this, but a suggestion to make this use case more ergonomic would be a nice shortcut like so:

import {cosmiconfig} from 'cosmiconfig';

cosmiconfig(namespace, {
  loaders: {
    noExt: '.js' // use the default .js loader
  }
});

This should work with custom loaders:

import {cosmiconfig} from 'cosmiconfig';
import {myLoader} from 'somewhere';

cosmiconfig(namespace, {
  loaders: {
    '.js': myLoader,
    noExt: '.js' // use myLoader
  }
});

Alternatively, expose the default loader functions at the module level, as previously named in v5.x; loadJson, loadYaml, etc.