feat: Truncate directory name to git root

[Froopity]

Documentation

This feature adds the ability to truncate the directory name to start at the current git repository root rather than filesystem root, similar to the Starship truncate_to_repo option.

Example

Usage

❯ set --universal pure_truncate_prompt_current_directory_to_git_root true

Questions for Maintainers

I wasn't sure whether this should be under CWD or Git, I chose CWD as it is not actually dependent on the git feature being enabled and changes the directory name rather than branch name.

There were also no examples in the documentation page of a section with two different enabled/disabled flags. Maybe it should be it's own feature? Would love some advice.

I also did not want to presume that it should be enabled by default, but I think it's pretty nice :)

Acceptance Checks

• Documentation is up-to-date:
  • Add entry in feature list of README.md ;
  • Add entry in features' overview in docs/ ;
  • Add section in feature list to document
    • Features' flag ;
    • Prompt symbol ;
• Default are defined in conf.d/pure.fish for:
  • Feature flag ;
  • Symbol ;
• Tests are passing (we can help you 🤗 ):
  • Configs are tested (cf. tests/_pure.test.fish) ;
  • Feature is tested in tests/feature_name.test.fish ;
• Customization is available ;
• Feature is implemented.