[split] Move zish theme to oh-my-fish/theme-zish

https://github.com/oh-my-fish/theme-zish

themes/zish/README.md

-## Zish
-
-Zhishen Wen's simple fun theme =)
-
-![zish](https://raw.githubusercontent.com/bpinto/oh-my-fish/master/themes/zish/zish_preview.png)
-
-#### Left prompt
-User, host, abbreviated path, and git branch info
-
-####Right prompt
-Time and exit code
-
-Enjoy!

themes/zish/fish_prompt.fish

-# name: Zish
-
-function _is_git_dirty
-  echo (command git status -s --ignore-submodules=dirty ^/dev/null)
-end
-
-function fish_prompt
-  set_color -o red
-  printf '┌─<'
-  set_color -o blue
-  printf '%s ' (whoami)
-  set_color $fish_color_autosuggestion[1]
-  printf '@ '
-  set_color cyan
-  printf '%s ' (hostname|cut -d . -f 1)
-  set_color $fish_color_autosuggestion[1]
-  printf 'in '
-  set_color -o green
-  printf '%s' (prompt_pwd)
-  set_color -o red
-  printf '>'
-  
-  echo
-  set_color -o red
-  printf '└─<'
-  set_color yellow
-  printf '%s' (__fish_git_prompt)
-  if [ (_is_git_dirty) ]
-    set_color blue
-    printf '* '
-  end
-  set_color -o red
-  printf '>──'
-  set_color yellow
-  printf '» '
-  set_color normal
-end
\ No newline at end of file

themes/zish/fish_right_prompt.fish

-function fish_right_prompt
-  set -l exit_code $status
-  if test $exit_code -ne 0
-    set_color red
-  else
-    set_color green
-  end
-  printf '%d' $exit_code
-  set_color yellow
-  printf ' < %s' (date +%H:%M:%S)
-  set_color normal
-end
\ No newline at end of file