Replace global $lang with system.language

mod/help.php

@@ -6,13 +6,13 @@
 use Friendica\App;
 use Friendica\Content\Nav;
 use Friendica\Content\Text\Markdown;
+use Friendica\Core\Config;
 use Friendica\Core\L10n;
 use Friendica\Core\System;
 
 function load_doc_file($s)
 {
-	global $lang;
-	if (!isset($lang)) $lang = 'en';
+	$lang = Config::get('system', 'language');
 	$b = basename($s);
 	$d = dirname($s);
 	if (file_exists("$d/$lang/$b")) {
@@ -30,8 +30,6 @@ function help_content(App $a)
 {
 	Nav::setSelected('help');
 
-	global $lang;
-
 	$text = '';
 
 	if ($a->argc > 1) {

mod/register.php

@@ -21,8 +21,6 @@ function register_post(App $a)
 {
 	check_form_security_token_redirectOnErr('/register', 'register');
 
-	global $lang;
-
 	$verified = 0;
 	$blocked  = 1;
 
@@ -123,7 +121,7 @@ function register_post(App $a)
 			dbesc(DateTimeFormat::utcNow()),
 			intval($user['uid']),
 			dbesc($result['password']),
-			dbesc($lang),
+			dbesc(Config::get('system', 'language')),
 			dbesc($_POST['permonlybox'])
 		);
 

mod/regmod.php

@@ -97,8 +97,6 @@ function user_deny($hash)
 
 function regmod_content(App $a)
 {
-	global $lang;
-
 	if (!local_user()) {
 		info(L10n::t('Please login.') . EOL);
 		$o = '<br /><br />' . Login::form($a->query_string, Config::get('config', 'register_policy') === REGISTER_CLOSED ? 0 : 1);