GHC user manual

[Takenobu Tani]

> We might also want to have "GHC User's Guide (master branch)" to be the one built last > night from master.  Or, at least, to have this linked from somewhere discoverable.

I see. What you intend is the master (HEAD) document.

I created the sub page for "GHC User's Guide" [1] and linked from the
right side-bar on wiki [2].

>From that page, I made it possible to find both latest and master.
I will brush up this page.

[1]: https://gitlab.haskell.org/ghc/ghc/wikis/ghc-users-guide
[2]: https://gitlab.haskell.org/ghc/ghc/wikis/home

Regards,
Takenobu