docs: reword copy-pasted description of callback

system/Debug/Exceptions.php

@@ -141,11 +141,7 @@ public function exceptionHandler(Throwable $exception)
  }
 
  /**
- * Even in PHP7, some errors make it through to the errorHandler, so
- * convert these to Exceptions and let the exception handler log it and
- * display it.
- *
- * This seems to be primarily when a user triggers it with trigger_error().
+ * The callback to be registered to `set_error_handler()`.
  *
  * @return bool
  *