Enhance autocomplete generation

[crodas]

This PR fixes #5474,

This PR enhances the autocomplete feature that is built-in ly forc. The first enhancement is to add support to generate a script for fig.

The second enhancement is to add support to let each plugin (automatically through cli_examples) dump its clap configuration. This configuration is shared to the main forc binary which creates a single autocomplete script for the requested shell that is also aware of every plugin. If a plugin uses cli_examples! macro this will automatically inherit this feature without any additional change.

~The third improvement, still under development, is to install automatically the autocomplete feature instead of printing to the stdout (to address https://github.com/FuelLabs/fuelup/issues/548)~ (This feature has been added on c7015d0c0ad13cd0fd9a88ea2ef8c4b19ad38f26)

Description

Checklist

• [x] I have linked to any relevant issues.
• [x] I have commented my code, particularly in hard-to-understand areas.
• [x] I have updated the documentation where relevant (API docs, the reference, and the Sway book).
• [x] I have added tests that prove my fix is effective or that my feature works.
• [x] I have added (or requested a maintainer to add) the necessary Breaking* or New Feature labels where relevant.
• [x] I have done my best to ensure that my PR adheres to the Fuel Labs Code Review Standards.
• [x] I have requested a review from the relevant team or maintainers.