chore: fix git commit "rev-list" (#38069)

Fix the copied & pasted messy code, fix #38067

Now, "limit=-1" means "no limit"

modules/git/gitcmd/error_test.go

@@ -0,0 +1,23 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package gitcmd
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIsStderr(t *testing.T) {
+	cases := []struct {
+		check  StderrWildcard
+		stderr string
+	}{
+		{StderrUnknownRevisionOrPath, "fatal: ambiguous argument 'origin': unknown revision or path not in the working tree...."},
+		{StderrNoMergeBase, "fatal: origin/main..HEAD: no merge base...."},
+	}
+	for _, tc := range cases {
+		assert.True(t, IsStderr(&runStdError{stderr: tc.stderr}, tc.check), "stderr: %s", tc.stderr)
+	}
+}