feat: added a flag to generate shell scripts for key bindings

[brianShan974]

Checklist

check the box if it is not applicable to your changes

• I have updated the README with the necessary documentation
• I have added unit tests
• I have added end-to-end tests
• I have linked all related issues or PRs

Description of the changes

• Added a new --key-bindings flag to generate shell key bindings for Bash/Zsh/Fish.
• Updated README with usage instructions.

Related to #852

[LoricAndre]

This looks very interesting ! We won't merge it right now because I'm working on a complete refactor and it will be a lot easier to rebase and merge your PR once it is done than to rebase the refactor onto main.
I'm curious though, would you be able to compare the binary size with and without this change please ?

[brianShan974]

This looks very interesting ! We won't merge it right now because I'm working on a complete refactor and it will be a lot easier to rebase and merge your PR once it is done than to rebase the refactor onto main. I'm curious though, would you be able to compare the binary size with and without this change please ?

Yeah, to be honest, I forgot about size issues. It turns out to be fine to me, though. On my Macbook Air M3, without my modification, the size of the binary is 3864368 bytes, which is 3.685MiB. With my modifications, the size is 3897936 bytes, which is 3.717MiB. The difference is 33568 bytes, which is 32.78KiB.