描述：

注册一个前台导航菜单

用法：

<?php register_nav_menu( $location, $description ); ?> 

参数：

$location

(string) (必填) 菜单别名.

默认值: None

$description

(string) (必填) 菜单描述.

默认值: None

示例：

<?php
add_action( 'after_setup_theme', 'register_my_menu' );
function register_my_menu() {
  register_nav_menu( 'primary', __( 'Primary Menu', 'theme-slug' ) );
}
?>

源文件：

/**
 * Register a navigation menu for a theme.
 *
 * @since 3.0.0
 *
 * @param string $location    Menu location identifier, like a slug.
 * @param string $description Menu location descriptive text.
 */
function register_nav_menu( $location, $description ) {
	register_nav_menus( array( $location => $description ) );
}