forbid help entry is missing the "list" option

[qeveren]

The help entry for the forbid tool is missing the "list" option, which is required for its "list all forbidden items" function; it instead indicates that using the command without any option will do this, which doesn't work.

Steps to reproduce:

1. Open DFHack launcher.
2. Enter the command forbid with no options.
3. Output tab of the launcher reports only, "Command finished successfully".