fix typo

[EFord36]

Hi,

I think this is a typo - thought I'd open a PR to fix it if so.

Another option would be to write user instead of read/reader since the GUI labels section immediately above uses user, so it might be more consistent to use the same term in both places to refer to the user/reader (or alternatively, switch user for reader in the other section).

While I'm here, thanks for Furo, it's great!