Allow multiple categories to be shown

[customcommander]

[…]Perhaps I can also make a fix that allows multiple categories to be shown. (See, for instance, that the code for addIndex lists two categories but only one shows up in the docs. I can't imagine this would be too hard to fix.)

Originally posted by @CrossEye in https://github.com/ramda/ramda/issues/2572#issuecomment-401800480