Added append equals, merge append. Fixed creating numeric arrays

pkg/yqlib/operator_collect_test.go

@@ -13,6 +13,14 @@ var collectOperatorScenarios = []expressionScenario{
 			"D0, P[], (!!seq)::[]\n",
 		},
 	},
+	{
+		skipDoc:    true,
+		document:   ``,
+		expression: `[3]`,
+		expected: []string{
+			"D0, P[], (!!seq)::- 3\n",
+		},
+	},
 	{
 		description: "Collect single",
 		document:    ``,