Haskell.nix's `default.nix` is now a function that needs to be called
and `hackage-package` can no longer rely on the default internal GHC so
`compiler-nix-name` needs to be specified explicitly.
* Make the haskell.nix import in the examples explicit
The examples used `import ./. {}` without explaining the commands should
be run from the haskell.nix repo root. To avoid confusion like this I
added fetching a tarball of the repo. This is less efficient when run
from the repo but works when run from anywhere and makes it clear we're
importing haskell.nix.
Added a couple urls and removed the urls on the lens component so as not
to confuse components with packages.
* Fix rephrase
The phrasing was left in a partially-rewritten state.
* Change wording and fix typo
* Minor fixes for consistency
Toon Nolten
John A. Lotoski
Domen Kožar