app_voicemail.c: Document VMSayName interruption behavior

ASTERISK-26424 #close

Change-Id: I797ad0ed302d0b3d2c90543eff5b7207ed08ecf0

apps/app_voicemail.c

@@ -315,6 +315,9 @@
 		<description>
 			<para>This application will say the recorded name of the voicemail user specified as the
 			argument to this application. If no context is provided, <literal>default</literal> is assumed.</para>
+			<para>Similar to the Background() application, playback of the recorded
+			name can be interrupted by entering an extension, which will be searched
+			for in the current context.</para>
 		</description>
 	</application>
 	<function name="VM_INFO" language="en_US">