PHPStan level 5 (#4110)

* Fix most PHPDocs errors
Contributes to https://github.com/FreshRSS/FreshRSS/issues/4103
https://phpstan.org/writing-php-code/phpdoc-types

* Avoid func_get_args
Use variadic syntax instead https://php.net/manual/functions.arguments#functions.variable-arg-list
And avoid dynamic functions names when possible to more easily identify calls and unused functions.
Contributes to https://github.com/FreshRSS/FreshRSS/issues/4103

* PHPStan level 3

* PHPStand level 4

* Update default to PHPStan level 4

* Towards level 5

* Fix level 4 regression

* Towards level 5

* Pass PHPStan level 5

* Towards level 6

* Remove erronenous regression from changelog
https://github.com/FreshRSS/FreshRSS/pull/4116

app/Models/SystemConfiguration.php

@@ -0,0 +1,28 @@
+<?php
+
+/**
+ * @property bool $allow_anonymous
+ * @property bool $allow_anonymous_refresh
+ * @property-read bool $allow_referrer
+ * @property-read bool $allow_robots
+ * @property bool $api_enabled
+ * @property string $archiving
+ * @property string $auth_type
+ * @property string $auto_update_url
+ * @property-read array<int,mixed> $curl_options
+ * @property string $default_user
+ * @property string $email_validation_token
+ * @property bool $force_email_validation
+ * @property-read bool $http_auth_auto_register
+ * @property-read string $http_auth_auto_register_email_field
+ * @property-read string $language
+ * @property array<string,int> $limits
+ * @property-read string $meta_description
+ * @property-read bool $pubsubhubbub_enabled
+ * @property-read string $salt
+ * @property-read bool $simplepie_syslog_enabled
+ * @property string $unsafe_autologin_enabled
+ */
+class FreshRSS_SystemConfiguration extends Minz_Configuration {
+
+}