[#7243] minor tweak

Author: xabbuh

contributing/code/conventions.rst

@@ -112,8 +112,9 @@ the Web Debug Toolbar or by the PHPUnit bridge).
 
 .. _`@-silencing operator`: https://php.net/manual/en/language.operators.errorcontrol.php
 
-When deprecating a whole class the error should be placed between namespace and
-use declarations, like in this example from `ArrayParserCache`_::
+When deprecating a whole class the ``trigger_error()`` call should be placed
+between the namespace and the use declarations, like in this example from
+`ArrayParserCache`_::
 
     namespace Symfony\Component\ExpressionLanguage\ParserCache;