Size hints in inputbox.

main.py

@@ -577,7 +577,7 @@ def tl_html_results_and_feedback_area(session, show_submit_form=True):
 
 
 def tl_html_render_inputbox(session, target_html_id, region_html_id):
-    txtarea = Textarea(id="ccodetoeval", name="ccodetoeval", placeholder="Paste a piece of C code here.", rows=3)
+    txtarea = Textarea(id="ccodetoeval", name="ccodetoeval", placeholder="Paste a standalone C program here. Larger than a 'Hello world', smaller than 1000 LoC.", rows=3)
     form = Form(Group(txtarea, Button("Evaluate")),
                 hx_post="/submit_to_eval",
                 hx_swap="outerHTML",