refactor: add various comments throughout the code, change argument/type names to more descriptive, add explicit types

[srghma]

just various comments while I was learning a code

I think non-ideal comment is better than no comments at all

[srghma]

answer on https://github.com/purescript-halogen/purescript-halogen-vdom/pull/38#issuecomment-629367556

ok, I agree that it's not good to change the name of arguments on this stage

but what about:

• adding types
• adding comments
• adding data STObject' which is like STObject but without region argument (allows to add types to some function, before it complained about escaped scolems)

[srghma]

I have noticed @thomashoneyman mentioned that during halogen v5 refactoring the

The type variables have been renamed to full words in the component / query / etc. type signatures. Maybe this will help, maybe not - feedback is welcome and appreciated!

maybe longer type variables are not so bad idea

[srghma]

also, halogen is using long arrows everywhere ->, halogen-vdom is using unicode arrows everywhere →