feat(bira): improve theme and add support for mercurial (#6631)

Added the red dot (instead of the default `*`) if the branch is dirty.

The bira theme only supported git, now it supports mercurial as well. It
needed ito call `hg_prompt_info` and the `ZSH_THEME_HG_PROMPT_`
variables.

Closes #6631

themes/bira.zsh-theme

@@ -1,32 +1,32 @@
-# ZSH Theme - Preview: https://gyazo.com/8becc8a7ed5ab54a0262a470555c3eed.png
 local return_code="%(?..%{$fg[red]%}%? ↵%{$reset_color%})"
+local user_host="%B%(!.%F{red}.%F{green})%n@%m %{$reset_color%}"
+local user_symbol='%(!.#.$)'
+local current_dir="%B%{$fg[blue]%}%~ %{$reset_color%}"
 
-if [[ $UID -eq 0 ]]; then
-    local user_host='%{$terminfo[bold]$fg[red]%}%n@%m %{$reset_color%}'
-    local user_symbol='#'
-else
-    local user_host='%{$terminfo[bold]$fg[green]%}%n@%m %{$reset_color%}'
-    local user_symbol='$'
-fi
-
-local current_dir='%{$terminfo[bold]$fg[blue]%}%~ %{$reset_color%}'
-local git_branch='$(git_prompt_info)'
+local vcs_branch='$(git_prompt_info)$(hg_prompt_info)'
 local rvm_ruby='$(ruby_prompt_info)'
 local venv_prompt='$(virtualenv_prompt_info)'
 
 ZSH_THEME_RVM_PROMPT_OPTIONS="i v g"
 
-PROMPT="╭─${user_host}${current_dir}${rvm_ruby}${git_branch}${venv_prompt}
+PROMPT="╭─${user_host}${current_dir}${rvm_ruby}${vcs_branch}${venv_prompt}
 ╰─%B${user_symbol}%b "
 RPROMPT="%B${return_code}%b"
 
 ZSH_THEME_GIT_PROMPT_PREFIX="%{$fg[yellow]%}‹"
 ZSH_THEME_GIT_PROMPT_SUFFIX="› %{$reset_color%}"
+ZSH_THEME_GIT_PROMPT_DIRTY="%{$fg[red]%}●%{$fg[yellow]%}"
+ZSH_THEME_GIT_PROMPT_CLEAN="%{$fg[yellow]%}"
+
+ZSH_THEME_HG_PROMPT_PREFIX="$ZSH_THEME_GIT_PROMPT_PREFIX"
+ZSH_THEME_HG_PROMPT_SUFFIX="$ZSH_THEME_GIT_PROMPT_SUFFIX"
+ZSH_THEME_HG_PROMPT_DIRTY="$ZSH_THEME_GIT_PROMPT_DIRTY"
+ZSH_THEME_HG_PROMPT_CLEAN="$ZSH_THEME_GIT_PROMPT_CLEAN"
 
 ZSH_THEME_RUBY_PROMPT_PREFIX="%{$fg[red]%}‹"
 ZSH_THEME_RUBY_PROMPT_SUFFIX="› %{$reset_color%}"
 
 ZSH_THEME_VIRTUAL_ENV_PROMPT_PREFIX="%{$fg[green]%}‹"
 ZSH_THEME_VIRTUAL_ENV_PROMPT_SUFFIX="› %{$reset_color%}"
-ZSH_THEME_VIRTUALENV_PREFIX=$ZSH_THEME_VIRTUAL_ENV_PROMPT_PREFIX
-ZSH_THEME_VIRTUALENV_SUFFIX=$ZSH_THEME_VIRTUAL_ENV_PROMPT_SUFFIX
+ZSH_THEME_VIRTUALENV_PREFIX="$ZSH_THEME_VIRTUAL_ENV_PROMPT_PREFIX"
+ZSH_THEME_VIRTUALENV_SUFFIX="$ZSH_THEME_VIRTUAL_ENV_PROMPT_SUFFIX"