Fix reverse engineering SQL issue for triggers when passed a single argument to trigger function. Fixes #4958.

docs/en_US/release_notes_4_16.rst

@@ -43,6 +43,7 @@ Bug fixes
 | `Issue #4935 <https://redmine.postgresql.org/issues/4935>`_ -  Fix accessibility issues.
 | `Issue #4952 <https://redmine.postgresql.org/issues/4952>`_ -  Fix an issue of retrieving properties for Compound Triggers. It's a regression of #4006.
 | `Issue #4953 <https://redmine.postgresql.org/issues/4953>`_ -  Fix an issue where pgAdmin4 unable to retrieve table node if the trigger is already disabled and the user clicks on Enable All.
+| `Issue #4958 <https://redmine.postgresql.org/issues/4958>`_ -  Fix reverse engineering SQL issue for triggers when passed a single argument to trigger function.
 | `Issue #4964 <https://redmine.postgresql.org/issues/4964>`_ -  Fix an issue where length and precision are not removed from table/column dialog.
 | `Issue #4965 <https://redmine.postgresql.org/issues/4965>`_ -  Fix an issue where the Interval data type is not displayed in the properties dialog of table/column.
 | `Issue #4966 <https://redmine.postgresql.org/issues/4966>`_ -  Fix 'Could not find the object on the server.' error while refreshing the check constraint.

web/pgadmin/browser/server_groups/servers/databases/schemas/tables/triggers/utils.py

@@ -120,7 +120,7 @@ def get_trigger_function_and_columns(conn, data, tid,
                 'tfunctions' in result['rows'][0]:
             data['tfunction'] = result['rows'][0]['tfunctions']
 
-        if len(data['custom_tgargs']) > 1:
+        if len(data['custom_tgargs']) > 0:
             # We know that trigger has more than 1 argument, let's join them
             # and convert it to string
             formatted_args = ["'{0}'".format(arg)