Align step failure log output with GitHub Actions (#927)

Fixes #926.

Before:

<img src="/attachments/a5ae9221-eee2-410a-964e-6103ce126df4" alt="image.png" width="400">

After:

<img width="400" alt="image.png" src="attachments/2f2d67c4-6080-4ec3-9ae5-df33e6479920">

Also gets rid of a bunch of emojis in the logging and the obsolete link to `nektos/act` and align some other error messages.

---
This PR was written with the help of Claude Opus 4.7

---------

Co-authored-by: Nicolas <bircni@icloud.com>
Reviewed-on: https://gitea.com/gitea/runner/pulls/927
Reviewed-by: Nicolas <bircni@icloud.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-committed-by: silverwind <me@silverwind.io>

act/container/host_environment.go

@@ -372,6 +372,10 @@ func (e *HostEnvironment) exec(ctx context.Context, command []string, cmdline st
 	}
 	err = cmd.Wait()
 	if err != nil {
+		var exitErr *exec.ExitError
+		if errors.As(err, &exitErr) {
+			return ExitCodeError(exitErr.ExitCode())
+		}
 		return err
 	}
 	if tty != nil {