* Adapt doc guide to new GFM features

* Adapt doc guide to new GFM features

* Adding remarks about HTML and tables

Addition to section 'Related Methods':  suggests adding differentiators to the names of related methods.

    Splits certain guidelines for singleton and instance method.
    Calls for instance method to not prefix anything (like RDoc itself for a Ruby-coded instance method); e.g.:
        count -> integer, not array.count,.
        <=> other -> integer or nil, not hash <=> other -> integer or nil.
    Groups previous guidelines into Arguments, Block, Return types, Aliases.

co-authored-by: Peter Zhu <peter@peterzhu.ca>
co-authored-by: Stan Lo <stan001212@gmail.com>