Help for cell magics issue: %%cmd?<enter> makes a newline not printing help immediately.

In [1]: %%writefile?
   ...:

When I type %%writefile?<enter>, it just creates a newline as above, but I expected it would print help message, though.

( reproduced on main branch at c14f8408f560e322c23936e1ff9f8c4b2ccb8611 )

Is this a spec?