doc: Add missing markup in CREATE EVENT TRIGGER page
Reported-by: rir
Discussion:
Backpatch-through: 9.6
@@ -23,7 +23,7 @@ PostgreSQL documentation
<synopsis>
CREATE EVENT TRIGGER <replaceable class="parameter">name</replaceable>
ON <replaceable class="parameter">event</replaceable>
- [ WHEN <replaceable class="parameter">filter_variable</replaceable> IN (filter_value [, ... ]) [ AND ... ] ]
+ [ WHEN <replaceable class="parameter">filter_variable</replaceable> IN (<replaceable class="parameter">filter_value</replaceable> [, ... ]) [ AND ... ] ]
EXECUTE { FUNCTION | PROCEDURE } <replaceable class="parameter">function_name</replaceable>()
</synopsis>
</refsynopsisdiv>
