📝 Update fastapi-cli UI examples in docs

[Zhongheng-Cheng]

Update fastapi-cli ui examples, corresponding to #13031, in multiple en doc files:

• The fastapi run main.py example in docs/en/docs/deployment/manually.md.
• The fastapi run --workers 4 main.py example in docs/en/docs/deployment/server-workers.md
• The fastapi dev main.py example in docs/en/docs/tutorial/first-steps.md
• The fastapi dev main.py example in docs/en/docs/tutorial/index.md

[github-actions]

📝 Docs preview for commit 44cae95 at: https://a54b950a.fastapitiangolo.pages.dev

Modified Pages

• https://a54b950a.fastapitiangolo.pages.dev/deployment/manually/ - (before)
• https://a54b950a.fastapitiangolo.pages.dev/deployment/server-workers/ - (before)
• https://a54b950a.fastapitiangolo.pages.dev/tutorial/ - (before)
• https://a54b950a.fastapitiangolo.pages.dev/tutorial/first-steps/ - (before)

[alejsdev]

Nice, thank you! @Zhongheng-Cheng 🤓 🚀