Vi-mode Feature Implementation

[kulabun]

Vi-mode Feature Implementation

Description

Implements Vi-Mode Feature. There are some difference with zsh's spaceship implementation:

• fishshell also allows to handle VISUAL and REPLACE_ONE modes and it use dedicated symbols for them in default fish_default_mode_prompt. So I add them too.
• Zsh's spaceship also provide two methods to enable/disable vim mode(actually its implementation just switch it from emacs to vim). For fishshell same methods already exists out of box: fish_vi_key_bindings and fish_default_key_bindings.

Also I have overridden default fish_mode_prompt to avoid duplication. I think it better to have it all out of box.

Motivation and Context

74

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Screenshots (if appropriate):

How Has This Been Tested?

• [ ] I have tested using MacOS
• [x] I have tested using Linux

Checklist:

• [x] I have checked that no other PR duplicates mine
• [x] My code follows the code style of this project.
• [x] My change requires a change to the documentation.
• [x] I have updated the documentation accordingly.
• [x] I have updated the tests accordingly.

[kulabun]

Hey @matchai , Thanks for your time spent to review this PR. Fixed it all.

[kulabun]

Wow, that's interesting. After my commit CI start failing with this:

not ok 142 Prints section when fish_vi_key_bindigs is set

operator: = expected: ' [I] ' received: ' [N] ' ...

Unfortunately right after running fish_vi_key_bindings CI have fish_bind_mode in 'normal' state instead of 'insert'.

Fixed it.