Update stlite starting code to be more LLM-friendly.

templates/stlite/stlite_starting_code.py

@@ -1,4 +1,13 @@
 import streamlit as st
 
-name = st.text_input('Your name')
-st.write("Hello,", name or "world")
+def greet(name):
+    return "Hello " + name + "!"
+
+name_input = st.text_input('Your name')
+greet_button = st.button('Greet')
+if greet_button:
+    st.write(greet(name_input))
+elif name_input:
+    st.write(greet(name_input))
+else:
+    st.write(greet('World'))