Feature: Get `help` command and `?` postfix operator to get documentation on object type

[tinmarino]

Well this one is pretty hard. Not sure I'll be able, I'm posting here to see if it triggers some interest.

[bduggan]

Just calling WHY on an object could be a start; then we can make use of core improvements, i.e. have \help DateTime just be like say DateTime.WHY

> say DateTime.WHY
No documentation available for type 'DateTime'.
Perhaps it can be found at https://docs.raku.org/type/DateTime