nebirhos: use short hostname in prompt

Fixes #6050

themes/nebirhos.zsh-theme

@@ -11,7 +11,7 @@ else
 fi
 
 # Get the host name (first 4 chars)
-HOST_PROMPT_="%{$fg_bold[red]%}@$HOST ➜ %{$fg_bold[cyan]%}%c "
+HOST_PROMPT_="%{$fg_bold[red]%}@%m ➜ %{$fg_bold[cyan]%}%c "
 GIT_PROMPT="%{$fg_bold[blue]%}\$(git_prompt_info)%{$fg_bold[blue]%} % %{$reset_color%}"
 PROMPT="$HOST_PROMPT_$RUBY_PROMPT_$GIT_PROMPT"