Display icon markup before post categories and tags

genesis.php

/**
 * Display icon markup before post categories and tags
 * @param  string $post_meta
 * @return string
 */
function nn_post_meta( $post_meta ) {

  $icon_category = "<i class=\'fa fa-folder-open\'></i>";
  $icon_tag = "<i class=\'fa fa-tag\'></i>";

  $post_meta = sprintf(
    '[post_categories before="%s"] [post_tags before="%s"]',
    $icon_category,
    $icon_tag
  );

  return $post_meta;

}
add_filter( 'genesis_post_meta', 'nn_post_meta' );