docs: update sample config

user_guide_src/source/general/errors/013.php

@@ -6,7 +6,8 @@
 
 class Logger extends BaseConfig
 {
-    // .. other properties
-
-    public $threshold = 5; // originally 4 but changed to 5 to log the warnings from the deprecations
+    // ...
+    // This must contain the log level (5 for LogLevel::WARNING) corresponding to $deprecationLogLevel.
+    public $threshold = (ENVIRONMENT === 'production') ? 4 : 9;
+    // ...
 }