chore: update KVs to read KV and KVs provided as inputs

errors_test.go

@@ -55,6 +55,13 @@ func TestV(t *testing.T) {
 
 		eqV(t, err, "str", "wrapped")
 	})
+
+	t.Run("when provided KVs should incorporate them as they are without key mapping", func(t *testing.T) {
+		err := errors.New("simple msg", errors.KVs(errors.KVs("unspread", "vals"), errors.KV{K: "indiv", V: "1"}))
+
+		eqV(t, err, "unspread", "vals")
+		eqV(t, err, "indiv", "1")
+	})
 }
 
 func eq[T comparable](t *testing.T, want, got T) bool {

options.go

@@ -82,6 +82,14 @@ func KVs(fields ...any) []KV {
 	for i := 0; i < len(fields); i += 2 {
 		var kv KV
 		switch t := fields[i].(type) {
+		case []KV:
+			out = append(out, t...)
+			i--
+			continue
+		case KV:
+			out = append(out, t)
+			i--
+			continue
 		case string:
 			kv.K = t
 		case fmt.Stringer: