Display a list of all character sets.
The D column contains the dimension of this character set. The CH
column contains the number of characters in a block of this character
set. The FINAL-BYTE column contains an ISO-2022
in the designation escape sequence for this character set in
ISO-2022-based coding systems.
With prefix ARG, the output format gets more cryptic,
but still shows the full information.
(fn ARG)