doc: Add missing description for DROP SUBSCRIPTION IF EXISTS.

Oversight in commit 665d1fad99.

Author: Peter Smith <smithpb2250@gmail.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/CAHut%2BPv72haFerrCdYdmF6hu6o2jKcGzkXehom%2BsP-JBBmOVDg%40mail.gmail.com
Backpatch-through: 14

diff --git a/doc/src/sgml/ref/drop_subscription.sgml b/doc/src/sgml/ref/drop_subscription.sgml
index 2a67bdea91310cceff7db14f4dbbda76718bd0b4..e07124fd66158cd5abc8416479036585dfe74cbe 100644 (file)
--- a/doc/src/sgml/ref/drop_subscription.sgml
+++ b/doc/src/sgml/ref/drop_subscription.sgml
@@ -49,6 +49,16 @@ DROP SUBSCRIPTION [ IF EXISTS ] <replaceable class="parameter">name</replaceable
   <title>Parameters</title>
 
   <variablelist>
+   <varlistentry>
+    <term><literal>IF EXISTS</literal></term>
+    <listitem>
+     <para>
+      Do not throw an error if the subscription does not exist. A notice is
+      issued in this case.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><replaceable class="parameter">name</replaceable></term>
     <listitem>