Add import for guess_lexer function

assistant.py

@@ -1,4 +1,4 @@
-#!./.venv/bin/python
+#!/bin/python
 # Chat with an intelligent assistant in your terminal
 from ollama import Client
 import re
@@ -6,7 +6,7 @@ import pyperclip
 import sys
 import argparse
 import pygments
-from pygments.lexers import get_lexer_by_name
+from pygments.lexers import get_lexer_by_name, guess_lexer
 from pygments.formatters import TerminalFormatter
 import os