Füge Fish Shell Completion hinzu

- Vollständige Completion für Fish Shell (completions/ntu.fish)
- Unterstützt alle Flags und Optionen
- Path-Completion für Verzeichnisse und Dateien
- README um Fish-Installation erweitert

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

README.md

@@ -88,10 +88,12 @@ sudo cp .NameToUnix.conf  /etc/NameToUnix/config.toml     # Copy config file to
 mkdir -p ~/.config/NameToUnix/                            # Create a personal config directory for NameToUnix
 cp .NameToUnix.conf ~/.config/NameToUnix/config.toml      # Copy config file to this personal directory
 
-# Bash-Completion (optional)
+# Shell-Completion (optional)
 sudo cp completions/ntu.bash /etc/bash_completion.d/ntu   # Bash completion
 # Oder für Zsh:
 sudo cp completions/_ntu /usr/share/zsh/site-functions/_ntu  # Zsh completion
+# Oder für Fish:
+sudo cp completions/ntu.fish /usr/share/fish/vendor_completions.d/ntu.fish  # Fish completion
 
 # Manpage (optional)
 sudo cp man/ntu.1 /usr/share/man/man1/                     # Install manual page