fix syntax highlighting

app.py

@@ -79,4 +79,7 @@ st.markdown(
 
 # display file content
 st.markdown("#### File content:")
-st.code(example["content"], language=chosen_language)
+if not example["lexable"]:
+    st.write(f"File can't be lexed so we remove syntax highlighting.\nContent:\n {example['content']}")
+else:
+    st.code(example["content"], language=chosen_language)