Add docs for theme_display_vi

README.md

@@ -107,6 +107,7 @@ set -g theme_newline_cursor yes
 
 - `theme_display_ruby`. Use `no` to completely hide all information about Ruby version. By default Ruby version displayed if there is the difference from default settings.
 - `theme_display_vagrant`. This feature is disabled by default, use `yes` to display Vagrant status in your prompt. Please note that only the VirtualBox and VMWare providers are supported.
+- `theme_display_vi`. By default the vi mode indicator will be shown if vi or hybrid key bindings are enabled. Use `no` to hide the indicator, or `force` to show the indicator.
 - `theme_show_exit_status`. Set this option to yes to have the prompt show the last exit code if it was non_zero instead of just the exclamation mark.
 - `theme_git_worktree_support`. If you do any git worktree shenanigans, setting this to `yes` will fix incorrect project-relative path display. If you don't do any git worktree shenanigans, leave it disabled. It's faster this way :)
 - `fish_prompt_pwd_dir_length`. bobthefish respects the Fish `$fish_prompt_pwd_dir_length` setting to abbreviate the prompt path. Set to `0` to show the full path, `1` (default) to show only the first character of each parent directory name, or any other number to show up to that many characters.