Fix #8933 - Isql SHOW PROCEDURE/FUNCTION doesn't show NOT NULL status for parameters

Author: asfernandes

src/isql/show.epp

@@ -4408,6 +4408,9 @@ static processing_state show_func(const QualifiedMetaString& name)
 				show_charsets(charset, collation);
 			}
 
+			if (!ARG.RDB$NULL_FLAG.NULL && ARG.RDB$NULL_FLAG)
+				isqlGlob.printf(" NOT NULL");
+
 			if (ARG.RDB$ARGUMENT_POSITION != FUN.RDB$RETURN_ARGUMENT) // input, try to show default and make Vlad happy.
 			{
 				if (!prm_default_source_null)
@@ -5316,6 +5319,9 @@ static processing_state show_proc(const std::optional<QualifiedMetaString>& name
 				show_charsets(charset, collation);
 			}
 
+			if (!PRM.RDB$NULL_FLAG.NULL && PRM.RDB$NULL_FLAG)
+				isqlGlob.printf(" NOT NULL");
+
 			if (PRM.RDB$PARAMETER_TYPE == 0) // input, try to show default and make Vlad happy.
 			{
 				if (!prm_default_source_null)