haskell-resource-pool: update to version 0.2.3.0
haskell-snap: update to version 0.13.2.7
haskell-threads: update to version 0.5.1.2
haskell-threadscope: update to version 0.2.4
haskell-defaults.nix: don't provide singletons on pre-7.8.x platforms
haskell-system-fileio: require Cabal >= 1.8
haskell-snap: jailbreak to fix build with lens 4.2
haskell-cabal-lenses: jailbreak to fix build
haskell-cabal-cargs: add version 0.6.1
haskell-cabal-cargs: jailbreak to fix build with recent versions of either, lens, and tasty

https://github.com/dan-t/cabal-cargs/issues/3
test-framework-smallcheck: 0.2
haskell-vty: add version 5.1.0
haskell-vty-5.1.0: jailbreak to fix build with lens 4.2
haskell-parsers: update to version 0.11.0.2

Unfortunately, there are still build errors with this package (see
https://github.com/ekmett/parsers/issues/39). We need the latest
version, though, because older ones won't work with the latest
attoparsec.
cabal-db: new expression
haskell-RepLib: do not build haddocks
nixos/graphite-service: make option descriptions end with '.'

Because that is how it is supposed to be.
nixos/graphite-service: clean up restartTriggers

Currently, the restartTriggers are abusing the systemd unit file in that
the cfg.carbon.config/storageAggregation/... option text is pasted into
the unit file. Even though this sort-of works (the service is restarted
if the config changes) this causes systemd to print error messages about
invalid sections (rightfully so!).

The correct use of restartTriggers is to list storage paths, which is
what this change does. If any of the
cfg.carbon/config/storageAggregation/... options change, configDir will
get a new hash. It is not as "fine grained" as the current version, but
it is not abusing the interface.

Also, remove unneeded 'waitress' in one of the restartTriggers, because
it is already listed as part of the service config.
cran-packages.nix: fix a couple of builds
haskell-hscolour: define the bootstap version of this package using 'extension' rather than by passing an additional parameter to it