diff --git a/doc/src/sgml/ref/pg_ctl-ref.sgml b/doc/src/sgml/ref/pg_ctl-ref.sgml
index e7c9a8320dc..cc9d8fd353c 100644
--- a/doc/src/sgml/ref/pg_ctl-ref.sgml
+++ b/doc/src/sgml/ref/pg_ctl-ref.sgml
@@ -68,8 +68,8 @@ PostgreSQL documentation
    <sbr>
    <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>
    <arg choice="plain">register</arg>