diff --git a/doc/src/sgml/ref/pg_ctl-ref.sgml b/doc/src/sgml/ref/pg_ctl-ref.sgml
index 638f3f18714..59d05c51019 100644
--- a/doc/src/sgml/ref/pg_ctl-ref.sgml
+++ b/doc/src/sgml/ref/pg_ctl-ref.sgml
@@ -79,8 +79,8 @@ PostgreSQL documentation
 
    <command>pg_ctl</command>
    <arg choice="plain">kill</arg>
-   <arg><replaceable>signal_name</replaceable></arg>
-   <arg><replaceable>process_id</replaceable></arg>
+   <arg choice="plain"><replaceable>signal_name</replaceable></arg>
+   <arg choice="plain"><replaceable>process_id</replaceable></arg>
    <sbr>
 
    <command>pg_ctl</command>