There are several ways you can approach this. I wouldn’t recommend deleting edit-comments.php as this is changing the core files, and your changes will be lost when you update WordPress.
htaccess
301 Redirect /wp-admin/edit-comments.php http://www.example.com/wp-admin/
OR functions.php
Part 1
// Redirect any user trying to access comments page
function custom_disable_comments_admin_menu_redirect() {
global $pagenow;
if ($pagenow === 'edit-comments.php') {
wp_redirect(admin_url()); exit;
}
}
add_action('admin_init', 'custom_disable_comments_admin_menu_redirect');
Part 2
// Remove the menu item for comments from the side
function custom_disable_comments_admin_menu() {
remove_menu_page('edit-comments.php');
}
add_action('admin_menu', 'custom_disable_comments_admin_menu');
Part 3
// Remove comments links from admin bar
function custom_disable_comments_admin_bar() {
if (is_admin_bar_showing()) {
remove_action('admin_bar_menu', 'wp_admin_bar_comments_menu', 60);
}
}
add_action('init', 'custom_disable_comments_admin_bar');