Add a autocompletation plugin for forgejo-cli - #13910

Fix #13909

Standards checklist:

• The PR title is descriptive.
• The PR doesn't replicate another PR which is already open.
• I have read the contribution guide and followed all the instructions.
• The code follows the code style guide detailed in the wiki.
• The code is mine or it's from somewhere with an MIT-compatible license.
• If I used AI tools (ChatGPT, Claude, Gemini, etc.) to assist with this contribution, I've disclosed it below.
• The code is efficient, to the best of my ability, and does not waste computer resources.
• The code is stable and I have tested it myself, to the best of my abilities.
• If the code introduces new aliases, I provide a valid use case for all plugin users down below.

Changes:

• I added a similar gh way to add the fj approach (it doesn't working for the moment)

Other comments:

This contribution wasn't generated by a LLM technology, all the code is writing manual.