[ci skip] Remove non-existent parameter from log_message() docs

Reported in #4671
diff --git a/user_guide_src/source/general/errors.rst b/user_guide_src/source/general/errors.rst
index 9c190fe..a1cc351 100644
--- a/user_guide_src/source/general/errors.rst
+++ b/user_guide_src/source/general/errors.rst
@@ -78,11 +78,10 @@
 	CodeIgniter automatically logs any ``show_404()`` calls. Setting the
 	optional second parameter to FALSE will skip logging.
 
-.. php:function:: log_message($level, $message, $php_error = FALSE)
+.. php:function:: log_message($level, $message)
 
 	:param	string	$level: Log level: 'error', 'debug' or 'info'
 	:param	string	$message: Message to log
-	:param	bool	$php_error: Whether we're logging a native PHP error message
 	:rtype:	void
 
 	This function lets you write messages to your log files. You must