What problem does this feature solve?

Sometimes we need html-webpack-pulgin handle html template for more flexable requirement, template like ejs, underscore and so on. Like html-webpack-pulgin does:

new HtmlWebpackPlugin({
  template: '!!handlebars!src/index.hbs'
})

What does the proposed API look like?

It seems the page can not support add template loader like below:

module.exports = {
  pages: {
    index: {
      entry: 'src/main.ts',
      template: ''!!handlebars!src/index.hbs',
      filename: 'index.html'
    }
  }
}

hope to add this feature, html-webpack-plugin has support this after all