General purpose reformating and rewording in (a few places). This should
also make markdown linting happier.
Prefer back-ticks wherever useful and use `console` for code blocks to
be executed on terminal.
Also, update references links wherever possible (including update from
'http://' to 'https://').
If ~/Library/Haskell does not exist, fall back to ~/.cabal/bin.
Ideally, we'd parse ~/.cabal/config here, but cabal does not provide an
interface to get configuration settings.