fishy theme: text indicators for $? and git status

The git status indicators were taken from sorin.zsh-theme and changed to
use ASCII symbols instead of Unicode ones because my preferred terminal
font, DejaVu Sans Mono, renders Unicode symbols poorly and also because
Unicode rendering is not available in standard Linux virtual terminals.

themes/fishy.zsh-theme

@@ -3,7 +3,18 @@
 local user_color='green'; [ $UID -eq 0 ] && user_color='red'
 PROMPT='%n@%m %{$fg[$user_color]%}%~%{$reset_color%}%(!.#.>) '
 PROMPT2='%{$fg[red]%}\ %{$reset_color%}'
-RPS1='%(?..%{$fg[red]%}%? ↵%{$reset_color%})$(git_prompt_info)'
 
-ZSH_THEME_GIT_PROMPT_PREFIX=" %{$fg[cyan]%}"
+local return_status="%{$fg_bold[red]%}%(?..%?)%{$reset_color%}"
-ZSH_THEME_GIT_PROMPT_SUFFIX="%{$reset_color%}"
+RPROMPT='${return_status}$(git_prompt_info)$(git_prompt_status)%{$reset_color%}'
+
+ZSH_THEME_GIT_PROMPT_PREFIX=" "
+ZSH_THEME_GIT_PROMPT_SUFFIX=""
+ZSH_THEME_GIT_PROMPT_DIRTY=""
+ZSH_THEME_GIT_PROMPT_CLEAN=""
+
+ZSH_THEME_GIT_PROMPT_ADDED="%{$fg_bold[green]%}+"
+ZSH_THEME_GIT_PROMPT_MODIFIED="%{$fg_bold[blue]%}!"
+ZSH_THEME_GIT_PROMPT_DELETED="%{$fg_bold[red]%}-"
+ZSH_THEME_GIT_PROMPT_RENAMED="%{$fg_bold[magenta]%}>"
+ZSH_THEME_GIT_PROMPT_UNMERGED="%{$fg_bold[yellow]%}#"
+ZSH_THEME_GIT_PROMPT_UNTRACKED="%{$fg_bold[cyan]%}?"