[DOCS] DEFERRABLE/NOT DEFERRABLE, what is a command?

Hi all,

can you please check this:

Feed starts here: https://twitter.com/FranckPachot/status/888867529954820097

... misunderstanding (or documentation issue) is here:

https://twitter.com/FranckPachot/status/889161387414622209

Maybe the documentation needs to be more clear on what a "command" is?

Thanks,

Daniel