This is the PHP that ACF generates:

'has_archive' => 'docs',

'rewrite' => array(

'slug' => 'doc',

),

To make it translatable it should be:

'has_archive' => _x( 'docs', 'slug', 'text-domain' ),

'rewrite' => array(

'slug' => _x( 'doc', 'slug', 'text-domain' )

),

It works if exists also:

add_filter('acf/settings/l10n_textdomain', 'custom_acf_settings_textdomain');

function custom_acf_settings_textdomain( $domain ) { return 'text-domain'; }