Rename `Cmd.ExecOutput` to `Cmd.CombinedOutput` to avoid confusion

We now have `Cmd.Spawn` and `Cmd.Exec`, to avoid confusion, we use `Cmd.CombinedOutput` for combined output.

cmd/cmd.go

@@ -37,7 +37,7 @@ func (cmd *Cmd) WithArgs(args ...string) *Cmd {
 	return cmd
 }
 
-func (cmd *Cmd) ExecOutput() (string, error) {
+func (cmd *Cmd) CombinedOutput() (string, error) {
 	output, err := exec.Command(cmd.Name, cmd.Args...).CombinedOutput()
 
 	return string(output), err

fixtures/test_repo.go

@@ -48,7 +48,7 @@ func (r *TestRepo) Setup() {
 
 func (r *TestRepo) clone(repo, dir string) error {
 	cmd := cmd.New("git").WithArgs("clone", repo, dir)
-	output, err := cmd.ExecOutput()
+	output, err := cmd.CombinedOutput()
 	if err != nil {
 		err = fmt.Errorf("error cloning %s to %s: %s", repo, dir, output)
 	}

git/git.go

@@ -130,7 +130,7 @@ func Show(sha string) (string, error) {
 	cmd := cmd.New("git")
 	cmd.WithArg("show").WithArg("-s").WithArg("--format=%s%n%+b").WithArg(sha)
 
-	output, err := cmd.ExecOutput()
+	output, err := cmd.CombinedOutput()
 	output = strings.TrimSpace(output)
 
 	return output, err
@@ -144,7 +144,7 @@ func Log(sha1, sha2 string) (string, error) {
 	shaRange := fmt.Sprintf("%s...%s", sha1, sha2)
 	execCmd.WithArg(shaRange)
 
-	outputs, err := execCmd.ExecOutput()
+	outputs, err := execCmd.CombinedOutput()
 	if err != nil {
 		return "", fmt.Errorf("Can't load git log %s..%s", sha1, sha2)
 	}
@@ -207,7 +207,7 @@ func execGitCmd(input ...string) (outputs []string, err error) {
 		cmd.WithArg(i)
 	}
 
-	out, err := cmd.ExecOutput()
+	out, err := cmd.CombinedOutput()
 	for _, line := range strings.Split(out, "\n") {
 		line = strings.TrimSpace(line)
 		if line != "" {