Add `help x` for help documentation

[0atman]

Similar to python's help() function, that'd be so good!

>>> help echo
"Writes and flushes the parameters to the standard output.[...]"

I don't know if this is possible with nim, I've asked here: https://stackoverflow.com/questions/61221599/nim-equivilant-to-pythons-help

[david-fortini]

is there any progress here? I would like to try something if no one is working on this already