adapt minor changers / fix tests

src/Core/Config/Capability/IManageConfigValues.php

@@ -59,12 +59,12 @@ interface IManageConfigValues
 	public function get(string $cat, string $key = null, $default_value = null);
 
 	/**
-	 * Returns true, if the current config cannot be changed
+	 * Returns true, if the current config can be changed
 	 *
 	 * @param string $cat The category of the configuration value
 	 * @param string $key The configuration key to query
 	 *
-	 * @return bool true, if set is disabled
+	 * @return bool true, if writing is possible
 	 */
 	public function isWritable(string $cat, string $key): bool;
 

src/Module/Admin/Storage.php

@@ -146,7 +146,7 @@ class Storage extends BaseAdmin
 			'$noconfig'              => DI::l10n()->t('This backend doesn\'t have custom settings'),
 			'$form_security_token'   => self::getFormSecurityToken("admin_storage"),
 			'$storagebackend_ro_txt' => !DI::config()->isWritable('storage', 'name') ? DI::l10n()->t('Changing the current backend is prohibited because it is set by an environment variable') : '',
-			'$is_writable' => DI::config()->isWritable('storage', 'name'),
+			'$is_writable'           => DI::config()->isWritable('storage', 'name'),
 			'$storagebackend'        => $current_storage_backend instanceof ICanWriteToStorage ? $current_storage_backend::getName() : DI::l10n()->t('Database (legacy)'),
 			'$availablestorageforms' => $available_storage_forms,
 		]);