Update fibonacci example

app.py

@@ -131,7 +131,7 @@ def generate(prompt, temperature=0.9, max_new_tokens=256, top_p=0.95, repetition
 
 examples = [
     "def print_hello_world():",
-    "def fibonacci(n):",
+    'def fibonacci(n: int) -> int:\n    """ Compute the n-th Fibonacci number. """',
     "class TransformerDecoder(nn.Module):",
     "class ComplexNumbers:"
 ]